Annotea is a framework that supports Semantic Web based collaboration and authoring via Annotea objects, such as social annotations, bookmarks, and topics. Social bookmarks and topics can be used for semantic authoring in many levels. They let ordinary users tag interesting Web documents with their own personal concepts (folksonomies). These concepts can be simple or form hierarchies, and they can be linked to more standard concepts when users become aware of them. Collections of the concepts and the bookmarks under them can be stored to bookmark documents or services as metadata and easily shared with other users. Annotea users can also literally semantically author pages with link collections and categories. They can use the title and description information of the topics and bookmarks to create the page content. This content from the bookmark and topics hierarchies is then easily converted to XHTML Web pages by using XSLT scripts. Annotea presentation objects further support authoring and customized presentations by separating the presentation and the application data. While Annotea precedes tagging and social bookmarking services and tools popular today it still provides better flexibility, extendibility, and reuse of the bookmark and topic data with help of the Semantic Web technologies.
Annotea is a framework for semantic annotations [
Ordinary users who are not familiar with semantic Web can do semantic authoring with intuitively familiar Annotea objects, such as annotations, discussions threads, bookmarks, and topics (tags). For instance, Annotea social bookmarks allow users to recall earlier visited Web resources, such as Web documents, services, music, images and blogs. As a side effect, the user also authors metadata about the bookmarked resources. When published and shared, this information can be useful not only for the user but also for other users and applications.
Users can also choose to use Annotea to author and maintain Web pages consisting of link collections and categories. In this case, users semantically author bookmark and topic information, such as title and description information, which can be used to form Web pages that were earlier manually written and maintained.
Annotea topics [
Annotea uses the Semantic Web technologies for implementing
the solutions but hides the Semantic Web from the ordinary
users under the familiar objects and easy user interfaces. From
the user point of view, the Annotea topics can be used for Web
tagging just like in the popular Web tagging services [
Annotea objects can be presented to the users in many
innovative ways and by different tools. Typically, the objects are
explored in the context of the Web resources they refer to,
examined in selected topic hierarchies, and searched by using
different properties. Amaya browser/editor [1] and lately
Annotea Ubimarks [7] have been used to demonstrate some
capabilities of Annotea objects. In addition, many other clients,
such as Annozilla [8], have been developed outside the Annotea
team. The bookmark files can also be presented in normal
browsers as XHTML pages by using selected XSLT style sheets.
In Annotea the bookmarks and topics can be stored locally or
shared both with individual users on different devices and with
different user groups. Unlike simple tagging or bookmark
formats, such as XBEL [
In addition to supporting tools for creating and retrieving bookmarks, the Annotea bookmarks can be used as user profiles for different services. This helps users find the information relevant to them at a certain context. Annotea bookmarks and topics can also contain information not just about the user but his or her social network. Again, this can be used to support the finding of more relevant information. Bookmarks and topics can also be used in applications organizing blog type information. Finally, as shared bookmarks are easy to create we hope to eventually see enough commonly available bookmark and topic data to be able to see network effects in applications using the published bookmark repositories collectively. These applications can provide more relevant results. Furthermore, when dat a mining and search engines type applications mine the topics and different connections between the topics it is possible to make many new innovative discoveries connecting fields that were not aware of each other because they used different terminologies.
Different annotation and tagging applications can be built on top of Annotea architecture that includes Annotea stores, Annotea objects, such as the bookmarks and topics, and protocols. Annotea stores are RDF metadata stores that store Annotea objects. Objects from various stores can be easily merged and viewed together. Many currently popular tagging services violate the principle of user control and do not give users a choice of where to store the bookmarks and topics. The Annotea objects can be stored in local files, global Web servers and/or Web documents containing the metadata.
Web documents offer users an easy alternative to get started without a server. The same authentication and protection mechanisms can be used as for any other Web document. A document can also be used to archive snapshots of the selected Annotea objects stored on the server. For instance, a version of a document can be stored together with annotations for that version.
Annotea objects have URIs and properties. They all store some
basic tracking information, such as who created them and when.
The Annotea schemas [2, 3, 6] define only a few specifically
Annotea related properties for Annotea objects. To improve
reuse and decrease unnecessary inferencing the rest of the
properties are adopted from other well-established schemas,
such as Dublin Core. Annotea usage documents [
New properties can be easily added to Annotea objects. For instance, Annotea Ubimarks lets the author add a URI to his personal and social network information by using foaf:maker (see Figure 1). When provided, this social network information can be used as additional help when trying to find related documents.
Annotea [
While the first phase of Annotea development concentrated on annotations, early on many user scenarios were developed, presented, and discussed about social bookmarks and topics (tags). These were implemented during the second development phase, when the need for categories was high on the users’ wish list. Especially status categories were needed to mark the processed annotations.
We wanted to make sure that Annotea could easily support not
only annotation categories but also our other scenarios related to
categories. We also wanted an easy user metaphor that would
work well with the already existing metaphors. As a result, we
decided to implement the social bookmark and topic objects as a
variation of the semantic annotations [
"http://www.med.harvard.edu/AANLIB/home.html"/> <foaf:maker RDF:resource =
"http://www.annotea.org/marja#marja"/> <bm:hasTopic RDF:resource = "http://mydomain.org/AnnoteaURI/exTopic"/> <RDFS:seeAlso RDF:resource =
"http://big.sfn.org/NDG/site/eavData.asp?o=28952"/> </bm:Bookmark>
The bookmark metaphor was great for our purposes. Ordinary users are not only familiar with it but have often used traditional bookmark interfaces. Furthermore, the bookmark user interfaces have a lot of enhancement possibilities that benefit from the Semantic Web approach. For instance, the user interface can utilize the document context to find similar bookmarks and topics..
Like other Annotea objects, the bookmark and the topic objects have their own identification URI. This URI ensures that Annotea objects retain their identity globally even when objects are merged together from different data stores, or moved to another location along with a bookmark file, or sent to another user by e-mail.
Not all users have their own Web domains. Therefore, the current Annotea Ubimarks implementation uses URIs that are unique UUIDs, such as "urn:uid:025f3d84-57bd-11da-924db619a79a047d". The UUIDs can be easily created without owning a Web domain. Resolving the objects content based on the UUID would need more work, but that is not usually a problem. .
Alternatively, the user can choose HTTP addresses in her own domain with date info by defining an URI path, for instance, "http://mydomain.org/AnnoteaURI/". Similarly, a bookmark server can create URIs. If the URI changes in the server or for some other reason, the correspondence between two Annotea objects can be defined by using the owl:sameAs property.
Annotea does not define all bookmark and topic properties by itself. It uses properties from well known vocabularies, such as Dublin Core. Applications already familiar with these properties know how to deal with them also in Annotea object context without any extra processing. RDF for a sample bookmark and a topic is presented in Figure 1.
Bookmarks and topics have many common properties with other Annotea objects. For instance, the objects can have a title (dc:title), a longer description (dc:description), information about their author (dc:creator and foaf:maker), the creation date (a:created), the modification date (dc:date), and links to other related information (RDFS:seeAlso)
In addition, a bookmark has information about the page it recalls (bm:recalls), and zero or more topics (bm:hasTopic). A topic has information about its parent topic (bm:subTopicOf). In addition, new properties can be easily added.
Annotea objects can be presented to users without a need to know anything about the Semantic Web. The bookmark metaphor nicely supports semantic authoring and presentation of Annotea bookmark and topic objects, their collections, and context sensitive views to these objects.
The Annotea topics can be anything the user wants them to be. They can start with vague meaning and gradually become more robust and better understood. When user discovers other related concepts in a better established ontologies, her own concepts can be linked to those.
Users can explore the bookmark or the topic information in simple forms. For instance, in Figure 2 the “Bookmark view” presents the bookmark’s RDF properties and values. Properties can be added to Annotea objects and different presentations may show different sets of properties. With guidance information about the properties, such as the presentation order and the preferred widgets, the presentations could be created automatically. This is the next step for the new Annotea presentation objects.
Annotea topics allow authors create and maintain shared
classifications or topics [
Context dependent views of Annotea objects are characteristic
to Annotea applications. For instance, Annotea Ubimarks user
interface provides information about related Web documents in
the current document context. When a user browses through the
Web pages and finds something interesting she can look for the
“Pagemarks” icon. This icon means that one or more users has
bookmarked the current page. The “Pagemarks” icon can be
clicked to open a view listing all the bookmarks on the page.
These bookmarks and their topics can be easily followed to find
related documents in the currently subscribed bookmark stores,
some of which may provide information from Web crawlers.
Users collaborating in related research areas can benefit from
the bookmark and topic information. They can find related
topics and bookmarks. For instance, in Figure 4 the user has
bookmarked a gene page in Amigo. When she browses the page
later and clicks the “Pagemarks” and the topic icons, she finds
more information about the genes involved in CML leukemia
made by other researchers in other departments of the institution
or in other institutions. In the future, the user generated
information can be combined with automatic categorizations,
such as created in MagPie [
The order of the bookmarks can be defined by using Annotea presentation objects [5]. They can be attached to another resource, such as a topic, to guide its presentation. For instance, it can define the order of the selected bookmarks under a topic. The rest of the topics are presented alphabetically. The presentation objects let users define customized orders for a shared hierarchy. A sample presentation object is presented in Figure 5.
The topic hierarchies do not have to have a common root topic.
It is possible to have several roots. This lets the user also view
hierarchies even when some topics are temporarily unavailable.
Hierarchies containing several root topics can be also viewed in
multifaceted displays, such as the ones used in mSpace [
Annotea has been pioneering with social bookmarking, tagging, and folksonomy applications on the Web. Annotea social bookmarks and topics provide ordinary users familiar metaphors for authoring and sharing reusable and easily extendible Semantic Web metadata without a need to learn or understand the Semantic Web.
Many Web pages containing links and categories can be chosen to be semantically authored as Annotea bookmark files and transformed with XSLT into XHTML pages. This makes maintaining the links easy.
Annotea users are not limited to use one service for their bookmarks and topics. They can subscribe several local or global data stores containing the various Annotea objects they are interested in at each moment. Web documents offer users an easy starting point. Semantic Web gives supports for easy merging and querying of Annotea metadata from several different sources.
Annotea object metadata is uniquely identifiable and includes information of its creator and creation dates. It can be easily extended, customized, combined, and reused in many applications and services. It can provide additional organization for data mining and search engine applications, chatrooms, and blogs.
Different views to the data, including document context dependent views, can be easily created. Overall, Annotea bookmarks and topics can provide huge benefits and flexibility for Semantic authoring without adding complexity for the user interface.
Many people including Jose Kahan, Eric Prud'hommeaux and Ralph Swick have contributed to Annotea.. I also want to thank Siegfried Handshuh, Martin Dzbor and Pat Croke for support and many inspiring discussions. 7. REFERENCES [1] Amaya homepage, http://www.w3.org/Amaya [2] Annotea annotation schema,
http://www.w3.org/2000/10/annotation-ns [3] Annotea bookmark schema,
http://www.w3.org/2002/01/bookmark# [4] Annotea homepage at W3C,
http://www.w3.org/2001/Annotea [5] Annotea presentation schema (draft),
http://www.annotea.org/schemas/2006/04/presentation [6] Annotea thread schema, http://www.w3.org/2001/03/thread [7] Annotea Ubimarks homepage,
http://www.annotea.org/mozilla/ubi.html [8] Annozilla home page, http://annozilla.mozdev.org/