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  <front>
    <journal-meta />
    <article-meta>
      <title-group>
        <article-title>Directing Status Messages to their Audience in Online Communities</article-title>
      </title-group>
      <contrib-group>
        <contrib contrib-type="author">
          <string-name>Milan Stankovic, Philippe Laublet</string-name>
          <email>milan@milstan.net</email>
          <email>milan@milstan.net, philippe.laublet@paris-sorbonne.fr</email>
          <email>philippe.laublet@paris-sorbonne.fr</email>
          <xref ref-type="aff" rid="aff1">1</xref>
        </contrib>
        <contrib contrib-type="author">
          <string-name>Alexandre Passant</string-name>
          <email>alexandre.passant@deri.org</email>
          <xref ref-type="aff" rid="aff0">0</xref>
        </contrib>
        <aff id="aff0">
          <label>0</label>
          <institution>Digital Enterprise Research Institute, NUI-Galway</institution>
          ,
          <addr-line>Galway</addr-line>
          ,
          <country country="IE">Ireland</country>
        </aff>
        <aff id="aff1">
          <label>1</label>
          <institution>LaLIC, Université Paris IV - Sorbonne</institution>
          ,
          <addr-line>Paris</addr-line>
          ,
          <country country="FR">France</country>
        </aff>
      </contrib-group>
      <abstract>
        <p>- In this paper we present the results of our user study about status message sharing on the Social Web. The study revealed the privacy and information noise (sometimes originating from gap of understanding and sometimes from lack of significance) to be the key problems in the domain and allowed us to unveil their nature. Further on we present the existing solutions and workarounds for those problems and introduce the idea that Semantic Web technologies could help confront those problems in a more complete way. We propose a way to use semantic descriptions of status messages, their intended audiences and distributed data about users to direct status messages to their intended recipients. Particularly, we rely on the Online Presence Ontology as a vocabulary for exposing status message semantics, and we provide necessary extensions to support status message directing.</p>
      </abstract>
      <kwd-group>
        <kwd>Faceted Identity</kwd>
        <kwd>Linked Data</kwd>
        <kwd>Online Presence</kwd>
        <kwd>Social Web</kwd>
        <kwd>Social Networks</kwd>
      </kwd-group>
    </article-meta>
  </front>
  <body>
    <sec id="sec-1">
      <title>I. INTRODUCTION</title>
      <p>Sdescribe the state of a user’s presence in the online world.</p>
      <p>TATUS messages are short textual expressions that
Sharing status messages on different social services on the
Web (Microblogging services, Instant Messaging platforms,
Social Networks) became a common practice for people to
share thoughts, feelings of the moment, announce one’s
presence in the online world and broadcast information.
However, as more and more users take part in status message
sharing, the open communities become overloaded with status
updates. Many problems arise from such an overload. Firstly,
confidentiality of status messages in open communities is a
significant question, since not all status messages are meant for
general public. Some should be kept private from certain
contacts who might use them in an inappropriate way. An
example could be a status message revealing somebody’s
drinking habits, meant to amuse personal friends, but the same
status message could be a source of inconvenience if shown to
work colleagues.</p>
      <p>Apart from private nature of some status messages there are
other reasons why a particular status message might not be
suitable for a certain audience. For example, some status
message updates may have no significance for certain groups
of contacts that consider them as information noise. It is a
common case that we subscribe to someone’s statuses because
of the interest in professional news he/she is sharing, but aside
we get a lot of postings about the person’s personal life that
don’t interest us. Problems like those limit in a great deal, the
usefulness of today’s status sharing services (mostly
microblogging services and Social Networks)</p>
      <p>In order to explore more deeply the nature of the problem of
confidentiality and other key problems in status message
sharing in large communities on the Social Web we conducted
a qualitative user study with subjects who are using status
messages for different purposes and in different contexts. The
goal of the study was to develop understanding of the key
problems, factors that make a status message open or
confidential – that determine its intended audience. Apart from
understanding the problems, the study allowed us to explore
the space of possible solutions. In Section 2 we present the
results of our user study. Section 3 presents the Presence
Diamond, a useful notion for the study of presence online as a
faceted phenomenon. Section 4 lists currently available
solutions for problems identified in the study. In Section 5 we
introduce a way to direct a status message to its intended
audience using Semantic Web technologies, and we show how
those technologies are flexible to support even dynamic
audience definitions (where members of the audience change
frequently). Section 6 presents related work and in Section 7
we conclude the paper.</p>
      <p>The user study was conducted through a series of ten
interviews with users of social networks and microblogging
platforms who have been using them for status message
sharing for some time (a year in average). The 30-35 minute
interviews were field-noted and audio recorded for further
reference. Users’ age ranged from 22 to 35. This choice
proved to correspond well to demographics of users of the
most active microblogging services (documented in a
statistical report done by Pew Internet1). Equal number of male
and female subjects, from France and Ireland, with different
origins and backgrounds, took part in the interviews.</p>
      <p>After a couple of questions about users’ background, users
were asked to tell their status message publishing experiences.
The main goal was to identify their context in the time of
publishing, nature of the status message content and the
intended audience. The inconveniences and the inability of
microblogging tools and social networks to meet their status
message sharing needs were also explored.</p>
      <p>Once we collected the user stories, we relied on Grounded
Theory inspired approach to extract relevant categories from
them, and further generalize the categories to super-categories
that we call – major issues. Open and Axial coding were used
with participation of two researchers in order to reduce the
impact of subjectivity.</p>
      <p>
        Grounded Theory was introduced by Glaser and Strauss [
        <xref ref-type="bibr" rid="ref1">1</xref>
        ]
and has served ever since for analysis of results in qualitative
research in Social Sciences. Grounded Theory is an approach
to looking systematically at qualitative data to derive codes
and group them into relevant categories that will further be
generalized into concepts that make the ground for generating
a theory. Generalizations are derived by thinking efforts of
researchers. Due to a space limit, in this paper we present only
a part of our findings - the highest level generalizations, and
we briefly describe them with some of the lower level
generalizations that we find the most relevant to our intended
readers.
      </p>
      <p>Generally we discovered that many times when users
publish a status message, they have a certain audience in mind.
The status message is intended for a particular audience either
because of its ability to understand the message (or the
inability of others to understand it properly) either because of
significance of the message for a certain group (and
insignificance for others) or because of the confidential nature
of the status message content. The next three sections present
those major issues – reasons why a status message has its
particular audience.</p>
      <sec id="sec-1-1">
        <title>A. Gap of Understanding</title>
        <p>In many cases where a certain status message is not meant
for a certain group of people it is because of their inability to
understand, properly interpret and maybe even reply to the
content of the message. Sometimes the inability arises from
shallow acquaintance like in cases where the user publishing
a status messages knows a certain group of people for a short
time. The shallowness of acquaintance can be an obstacle for
this group of people to understand jokes, metaphors and
properly interpret the intended meanings of status messages.
Sometimes the gap of understanding results from lack of
competence like in cases where users use status messages to
ask for advice, or provoke professional discussions. This
problem is also present in scenarios of automatic postings of
status messages across services (e.g. automatic forwarding
from Twitter to Facebook) where mostly different audiences
are present on different services. Quite often personal friends
from one service (Facebook in our case) don’t understand and
find irrelevant the profession-related status messages posted on
another service (Twitter in our case).</p>
        <p>Some status messages bear a socially established meaning,
understood by a small community of people, like those
containing internal jokes, or internal aliases and metaphors.
Such status messages may be misinterpreted by people outside
that small community and may be source of
misunderstandings, inappropriate comments and other
inconveniences.</p>
      </sec>
      <sec id="sec-1-2">
        <title>B. Lack of Significance</title>
        <p>In other cases, a status message is not intended for some
people simply because they have no interest in it. This is the
case when a status message relates to a certain domain and
thus can be of significance only to people with an interest in
the domain. This case is common when people make
connections based on a shared interest, stay in touch and then
use status messages to spread domain related news, announce
events and provoke discussions. In some cases it is the interest
in the domain that makes a certain group of people not
interested in other non domain-related status messages of a
user. For people who are not familiar with the domain such
messages can represent noise.</p>
        <p>In other cases some groups of people might not be able to
make use of the information in the status message which has
an informative purpose. This is the case with status messages
highly dependent on location – like those containing
invitations to local parties and announcements of local events.
In both cases such status messages are irrelevant to people
from other locations who could not make use of the
announcement.</p>
      </sec>
      <sec id="sec-1-3">
        <title>C. Privacy</title>
        <p>Privacy is an issue that occurs when a user wants to
explicitly restrict access to some groups of contacts for some
types of status message or even only for a particular status
message. It is usually related to groups of higher granularity,
like the case of separating status messages for work and
private contacts. People usually perceive some content types
(like feelings and moods or travel experiences) to be suitable
only for closer contacts or contacts of a more private nature,
while those status messages should be kept private from some
other (more professional) groups of contacts.</p>
        <p>Some users, on the other hand express concern about the
possibilities to track their status messages to the past and
draw conclusions about their personality which would be out
of their control. The concern is expressed about the
uncontrolled data integration possibilities across services and
attempts to integrate status messages with other content about
the user and thus perform some spy-like behavior.</p>
      </sec>
    </sec>
    <sec id="sec-2">
      <title>III. THE PRESENCE DIAMOND</title>
      <p>Once we acknowledge that many status messages have an
intended audience and that access to them should in some
cases be restricted to that particular audience (in cases of
confidential messages), it becomes clear that one user might
have different status messages for different audiences at the
same time.</p>
      <p>In fact, emitting different information (appearances) to
different groups of observers is not restricted to status
messages, but spans the whole notion of online presence. By
the term online presence we refer to the totality of information
that allows perceiving one’s presence in online communities.
Apart from status messages as an element of presence,
availability for interaction might also have a faceted nature and
be different for different groups at different times. One can
easily imagine a working situation where a user is available for
interaction only with his work colleagues and busy for all the
others. Access to different presence information might also be
given only to specific groups of contacts (like in the case of
sharing the current location only with closest friends).</p>
      <p>Therefore, there is a need to look at the notion of online
presence as a faceted phenomenon. For this reason we
introduce the notion of the presence diamond (Figure 1.) to
capture the faceted nature of presence and the need to appear
differently to different groups of people.</p>
      <p>The notion of presence diamond allows us to look at a
person’s online presence as a diamond whereby different
observers are introduced to different facets of the diamond.
Facets differ among themselves in different types of presence
data that is accessible by observers of a facet (like in cases
where one group of observers can access a person’s location,
availability and a status message, and another group can access
only the status message), different granularity of data (like
in the case of sharing the exact location with closest friends
and only the current city/country with strangers), and in
different data that is emitted to different observers (like
having different status messages and different availability for
different groups of contacts).</p>
      <p>Even though we focus on status messages in this paper, we
will look at the problem of directing status messages to their
intended audience as a sub-problem of enabling faceted online
presence, and will therefore favor solutions general enough to
address the faceted nature of presence as a whole.</p>
      <p>IV. INCOMPLETE WAYS TO DEAL WITH STATUS MESSAGE</p>
      <p>DIRECTING
Some ways to direct status message updates to a particular
audience already exist. In this section we present the
workarounds found and applied by users, as well as solutions
developed as features of Social Web sites. For each of these
solutions we discuss its incompleteness.</p>
      <sec id="sec-2-1">
        <title>A. User Workarounds</title>
        <p>Some users manage to separate their contacts on different
Social Web services, by taking into account the nature of
relationship with a particular contact. For example, a number
of users maintain a list of work-related contacts on twitter
while having a more personal network of friends on Facebook,
and then share different status message updates for the
different audiences. This way status messages related to
private life can be kept confidential from work colleagues, and
personal friends don’t have to be bothered by work related
postings. However, the fact that some contacts use only one
social network stands in the way of such a separation. If some
of the user’s work colleagues use only Facebook, then
maintaining the separation would mean not connecting at all
with those persons. Apart from this limitation, if the separation
by purpose is not done at the start, it is hard to impose it once
the user has accepted different types of contacts to his/her
social network.</p>
        <p>Another way to deal with the identified issues is just to
restrict oneself to publishing only status messages acceptable
for the wide audience. Some users choose not to publish too
personal status messages because work-related contacts might
see them, and not to publish work-related status messages
because they might not be of interest to their friends. This
approach limits the potential of status message sharing in a
great deal excluding many professional and staying-in-touch
use cases.</p>
      </sec>
      <sec id="sec-2-2">
        <title>B. Solutions developed by Social Web Sites</title>
        <p>Solutions for niche microblogging and micro-broadcasting
began to emerge recently. Those Social Web sites allow for
broadcasting of status messages in closed communities (like in
ShoutEm3) or to people gathered around a certain interest (like
in Static4). However they mostly require intended recipients of
the status message updates to join each closed community
which can get quite complicated having in mind the number of
intended audiences a user might have. This approach certainly
leads to social network fatigue – a phenomenon of loss of
motivation to participate in yet another social network when
confronted with joining many social networks and building
identities on them.</p>
        <p>The new service E5 can be used to manage adding different
people to different social networks according to the nature of
the acquaintance (e.g. adding friends to Facebook and business
contacts to MySpace). However, it is hard to enforce this
separation since not all users are present on each of those
networks and therefore some of connections might be lost if
they do not meet the purpose one user has given to his/her
social network account.</p>
        <p>2 The figure and the notion of the Presence Diamond are strongly inspired
by the notion of the diamond of digital identity, that Mike Roch, Director of
IT Services at University of Reading, introduced at the Eduserv Digital
Identity Workshop in London, January 08, 2009</p>
      </sec>
    </sec>
    <sec id="sec-3">
      <title>3 http://www.shoutem.com/</title>
      <p>4 http://www.static.com/
5 http://www.mynameise.com/</p>
    </sec>
    <sec id="sec-4">
      <title>V. THE LINKED DATA WAY</title>
      <p>
        The term Linked Data [
        <xref ref-type="bibr" rid="ref2">2</xref>
        ] refers to publishing and
interlinking structured data on the Web in RDF6 with the
assumption that the value and usefulness of data increases the
more it is interlinked with other data. This effort to publish the
data online using open standards and interlink data sources is
aimed at transforming the Web of documents towards a more
(re)usable, machine readable Web of Data.
      </p>
      <p>We argue that additional semantics describing a status
message, as well as semantics (partially already published as
Linked Data) describing users and their current context can be
helpful to direct a status message to its intended audience, and
thus reduce information noise and contribute to ensuring
privacy. In particular we argue that currently available Linked
Data sources can help define the intended audiences of status
messages, relying on user properties described in those sources
(interests, locations, social graph, etc.)</p>
      <p>
        To enable publishing and exchange of such additional
semantics, we decided to enrich an existing vocabulary - the
Online Presence Ontology (OPO)7 - with the information about
intended audience of a status message. The Online Presence
Ontology presented in [
        <xref ref-type="bibr" rid="ref3">3</xref>
        ] provides a way to describe a user’s
current state of presence in the online world, including his/her
availability for interaction, current status message, location
and other elements of context. As such this vocabulary can be
elegantly complemented with a way to direct a status message
(or even the whole notion of Online Presence) to a certain
audience. To enable this, we have extended the OPO with the
notion of Sharing Space.
A Sharing Space, in our specification, is a group of people
(or agents) with whom particular information can be shared.
As shown on Figure 2, the OnlinePresence, encompassing
(among other properties) the current status message of a user,
can be connected to its intended audience through a property
intendedFor by linking it with the notion of SharingSpace.
The status message itself is represented using the Item concept
from the SIOC8 [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ] ontology in order to enable replies to the
status message and make use of this concept’s suitable
semantics. Sharing Space is also enriched with a list of
properties to allow representing of the common attributes that
bound members of the Sharing Space together (e.g., common
interest, common current location). In order to express the
6 Resource Description Framework http://www.w3.org/RDF/
7 http://www.milanstankovic.org/opo/
8 http://sioc-project.org/
semantics of those attributes we relied on concepts from
widely used vocabularies (FOAF9, SWC10, WGS8411). For
more details about the ontology design we refer the readers to
the project website and the ontology specification12.
      </p>
      <p>By identifying people who are intended to receive a status
message, the notion of Sharing Space can help software
systems to deliver status messages to specific people (members
of the Sharing Space) and thus deal with information noise and
even ensure confidential status message exchange.</p>
      <p>In order to properly define Sharing Spaces according to the
needs of real life scenarios, we will rely on the results of our
user study, presented in Section 2. According to our study
results, some of the major ways to define the intended
audience are: friends of a certain friend; people having a
certain interest; friends from a particular online community;
people being in a certain location; people having a certain
nature of relationship with the user; people who were affiliated
in the same institution; and custom assembled groups of
contacts.</p>
      <p>
        A lot of information needed to define those groups (users’
current and permanent locations, interests, friends’ lists, etc.)
is already available on the Social Web, and many sources
already publish this data using vocabularies such as FOAF and
SIOC [
        <xref ref-type="bibr" rid="ref4">4</xref>
        ]. Relying on those existing resources, Sharing Spaces
could be dynamically defined using simple SPARQL13 queries
that could identify the members of a particular Sharing Space
by collecting data across different data sources. We believe
that this way of defining Sharing Spaces is flexible enough to
cover the needs of real life scenarios identified in our user
study, and we will illustrate it on an example in the following
subsection.
      </p>
      <p>
        When proposing to use data from various distributed
datasets, we should acknowledge that executing queries over
distributed datasets might be a challenging task. However, this
challenge has already attracted researchers to develop
solutions for this distributed scenario. One of them is a system
DARQ [
        <xref ref-type="bibr" rid="ref5">5</xref>
        ], an engine for federated SPARQL queries.
      </p>
      <p>
        Apart from specifying Sharing Space members using
SPARQL, the new version of the OWL language14, currently
available as OWL 2 Working Draft [
        <xref ref-type="bibr" rid="ref6">6</xref>
        ] will provide a way to
define Sharing Spaces through richer restriction axioms such
as property chains. Property chains would allow to state that if
a user satisfies a certain property then he is automatically a
member of a Sharing Space. We also believe that the emerging
Rule Interchange Format [
        <xref ref-type="bibr" rid="ref7">7</xref>
        ] (currently a working draft) will
be a useful way to define and exchange Sharing Space
definition rules across different systems that may use different
rule languages internally.
      </p>
    </sec>
    <sec id="sec-5">
      <title>9 Friend-f-a-Friend vocabulary http://xmlns.com/foaf/spec/</title>
      <p>10 Semantic Web Conference Ontology
http://data.semanticweb.org/ns/swc/swc_2009-05-09.html
11 World Geodetic System ontology http://www.w3.org/2003/01/geo/
12 Other properties and classes introduced to support the notion of Sharing
Space can be found in the specification document
http://www.milanstankovic.org/opo/specs/
13 http://www.w3.org/TR/rdf-sparql-query/
14 http://www.w3.org/2004/OWL/</p>
      <sec id="sec-5-1">
        <title>A. Scenario of Use</title>
        <p>To better illustrate the flexibility of our approach and the
usefulness of Linked Data, we present a scenario of publishing
a status message together with a dedication to a particular
Sharing Space. Figure 3 will serve as a graphical support to
our explanations.</p>
        <p>In this scenario, our example user Harry is organizing a
reunion for his friends from the Semantic Web community.
The reunion will take place in Paris, and Harry wants to
announce it in his status message.</p>
        <p>Thanks to the open nature of Semantic Web technologies,
any status message publishing service (including
microblogging platforms, social networks, chat platforms) can
publish a status message and describe it using the OPO
vocabulary. So, Harry’s status message publishing service can
make the semantically described message available to all status
message consuming services. It can further associate it with a
particular audience, by using the intendedFor property and
the concept of a SharingSpace. Along with OPO data about
the status message itself, Harry’s service can publish a
SPARQL query to define the members of the Sharing Space.
In our case, since Harry’s message is intended for people
interested in Semantic Web who are currently in Paris, the
SPARQL Query would look like shown on Figure 4.</p>
        <p>To make better use of the data available in Linked Data
sources, we can reuse existing URIs used by those sources. In
our example we rely on the Geonames15 URI for Paris, to
uniquely identify this geographical location.</p>
        <p>Once the message is available together with its semantic
description, and a Sharing Space definition, other services can
consume it and make it available to their users. Let us take
another example user, Sally. She is Harry’s friend, interested
in Semantic Web and currently visiting Paris (according to her
last published status message with associated geographic
location information). Although Sally is not using the same
status message publishing service as Harry, her Social
Network (SN) service, can retrieve semantically described
status messages and SPARQL queries defining Sharing
Spaces. Since information about Sally’s interest is available in
one of her FOAF files, and available to her SN, and since her
current location is also known to SN, applying the SPARQL
query from Figure 4 will put Sally in SWPeopleInParis
Sharing Space - the one Harry’s status message is intended for.</p>
        <p>Sally’s interface for browsing status messages can now
make sure that status messages intended for her get to her
attention and somehow stand out from the abundance of other
status messages put online by her friends and other people.</p>
        <p>PREFIX opo: &lt;http://http://ggg.milanstankovic.org/opo/ns#&gt;
PREFIX foaf: &lt;http://xmlns.com/foaf/0.1/&gt;
PREFIX rdf: &lt;http://www.w3.org/1999/02/22-rdf-syntax-ns#&gt;
CONSTRUCT
{
}
WHERE
{
&lt;http://example.org/ns#SWPeopleInParis&gt;
rdf:type opo:SharingSpace;
foaf:member ?person.
}
?person foaf:topic_interest</p>
        <p>&lt;http://dbpedia.org/resource/Semantic_Web&gt;.
?person opo:declaresOnlinePresence ?presence .
?presence opo:currentLocation</p>
        <p>&lt;http://sws.geonames.org/2988507/&gt;.</p>
      </sec>
      <sec id="sec-5-2">
        <title>B. Some Benefits of Sharing Spaces</title>
        <p>Using the definitions of Sharing Spaces, like those shown in
this paper, and publishing status messages that rely on the
extended OPO vocabulary can help direct a status message to
its audience. As opposed to solutions where particular
(sometimes even closed) services are used to dedicate a status
message to a certain group of people, our approach offers a
way to dedicate a status message to a certain audience
regardless of the service being used to publish them and
present them. It is the use of widely accepted Semantic Web
standards (e.g., RDF(S) and OWL) that make the intended
audience specifications universal and thus applicable
everywhere.</p>
        <p>The approach also allows to take into account the ever
changing nature of user-related data, since membership in a
Sharing Space can be defined through a property and not by
naming particular members. Therefore users can belong to a
sharing space at one time when they satisfy a certain condition
(e.g. currently located in Paris), and not belong to it at all other
times.</p>
        <p>
          Apart from combating status message overload and helping
relevant messages to reach their audience, Sharing Spaces can
serve as a ground for ensuring privacy and confidential status
message sharing. Our approach is based on the idea [
          <xref ref-type="bibr" rid="ref8">8</xref>
          ] that
ensuring trust and privacy on the future Web can be grounded
on the interlinked graph of data (i.e. Linked Data) and policies
that take advantage of existing data sources. The introduced
change in the OPO vocabulary is a first step in this direction,
allowing to specify the intended audience of a status message
by reusing existing (linked) data on the Web. Further
mechanisms to enforce the delivery of a status message to the
specified intended audience can be built on top of our
presented solution. The advantage of this approach is that
dedicating a status message to its audience is quite a general
solution, addressing at the same time the challenge of dealing
with information noise, and being the ground for ensuring the
confidential status message sharing.
        </p>
        <p>VI. RELATED WORK</p>
        <p>
          Similar to our use of SPARQL to define sharing spaces i.e.
intended audience groups, Alessandra Toninelli et al. [
          <xref ref-type="bibr" rid="ref9">9</xref>
          ] use
RDF and SPARQL triple patterns to build social graph aware
policies. Using triple patterns different policies can be created
to grant access to user’s attention (e.g., ring her phone).
However this work is more related to mobile devices as it
strongly reflects the specifics of communication using a mobile
device, and in this sense it is complementary to our work in
effort to make use of social data available in Linked Data
sources to enhance user’s interaction with devices and make
her communications more adapted to her current situation.
Another point of difference is that the socially-aware policy
model is more concerned at granting/restricting access to a
certain resource than dedicating/directing presence information
to a certain audience.
        </p>
      </sec>
    </sec>
    <sec id="sec-6">
      <title>VII. CONCLUSIONS AND FUTURE WORK</title>
      <p>In this paper we presented the results of our user study,
based on qualitative research techniques, which was aimed at
identifying the nature of problems surrounding status message
publishing. Our study emphasized the need to direct a status
message to a particular audience in order to deal with major
issues like: Lack of Understanding, Significance, and Privacy.</p>
      <p>We have shown how users try to deal with those issues and
what solutions did the Social Web sites come up with to help
with directing a status message to a certain audience.
However, we judged all those solutions as incomplete either
because they require users to join particular status sharing
networks or because they restrain users from publishing certain
types of status messages.</p>
      <p>Our solution to the problem of dedicating a status message
to a particular audience is based on providing semantic
descriptions of intended audience and taking advantage of
existing data about users published as Linked Data on the
Web. Particularly we rely on a small extension of the Online
Presence Ontology that allows for associating the intended
audience information to a status message. Since the solution is
based on Semantic Web technologies it allows a high level of
interoperability and gives the intended audience information
the ability to flow across different status message sharing
services. Moreover, our semantic descriptions of intended
audiences possess the ability to collect the intended audience
members information from different Linked Data sources
across the Web, which makes them universal.</p>
      <p>
        Our future work will consist in evaluating the practical
aspects of our proposal by extending the distributed
microblogging platform SMOB16, described in [
        <xref ref-type="bibr" rid="ref10">10</xref>
        ] to publish
and take into account the intended audience information
through the use of new notion of Sharing Space introduced in
the Online Presence Ontology. The new version of SMOB will
make use of data available as Linked Data on the Web to
create refined descriptions of audience for its status messages.
      </p>
      <p>
        While the simple publishing and taking into account of
intended audience information would be sufficient to combat
the information noise problem, encompassing both issues of
Lack of Understanding and Significance; some additional
access control mechanisms must be employed to ensure that
the intended audience specifications are properly applied
across the Web. As a solution to access control we are
considering to use the FOAF + SSL protocol [
        <xref ref-type="bibr" rid="ref11">11</xref>
        ] – a
lightweight solution for authentication and authorization,
based on the semantics exposed using the widespread FOAF
vocabulary. The OpenID17 framework for providing a single
digital identity across the internet can also elegantly contribute
to achieve simple access control. OAuth18 authorization
protocol could also be helpful in ensuring secure exchange of
intended audience information across different services on the
Social Web.
      </p>
      <p>Although our solution for directing a status message to its
audience is flexible in specifying the intended recipients of the
status message, a lot of work remains to be done to ensure that
the unintended recipients do not get access to it. We see the
presented extension of OPO and the notion of Sharing Space
as a first step in this direction.</p>
    </sec>
    <sec id="sec-7">
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