:me owl:sameAs flickr:33669349@N00 . Alexandre Passant LaLIC, Université Paris-Sorbonne 28, rue Serpente 75006 Paris, France alexandre.passant@paris4.sorbonne.fr ABSTRACT ties and links with other people (foaf:knows) retrieved In order to release the Social Semantic Web and solve data- from his Flickr contacts; portability issues, there is a need from Web 2.0 providers • SIOC - as a model to describe activities of online com- to open their content and deliver it in a machine-readable munities, recently accepted as a W3C submission, SIOC way. Modeling it with vocabularies such as FOAF, SIOC, is used to represent user accounts (sioc:User) related as well as reusing data from the Linked Data initiative like to their owner (foaf:holdsAccount) and groups they DBpedia or GeoNames can help to achieve this task. The may belong to (sioc:UserGroup and sioc:member_of). goal of this demo is to showcase an RDF exporter for Flickr Moreover, the SIOC types module4 is used to represent profiles that acts such a way. user galleries (sioct:ImageGallery and sioc:owner_of); Keywords • GeoNames5 - since Flickr allows any user to mention his location, the script relies on the GeoNames web- Web 2.0, Linked Data, Social Networks, Data Portability, service6 to find the related place URI, and thus uses Flickr, FOAF, SIOC the geonames:locatedIn property and URI of exist- ing geonames:Feature resource to link a user to its 1. EXPORTER OVERVIEW location. Since most geonames:Feature instances are Describing people, user accounts and content using Se- linked to DBPedia[1] with owl:sameAs, it offers an au- mantic Web technologies offers standardized ways to query, tomatic way to link the profile to other URIs. Yet, browse and reuse it. Moreover, it lets this data enter the this feature may give incorrect results if the location Linked Data Web rather than being part of a closed-world, has not been precisely defined; proprietary, data silo. The Flickr wrapper1 described here • Lingvoj7 - since Flickr groups administrators can de- provides a way to model a Flickr user account in RDF using fine the language used in their groups, the Lingvoj vo- well-known vocabularies like FOAF[4] and SIOC[3]. It is a cabulary is used in association with DublinCore to rep- simple application that uses PHP bindings2 for the Flickr resent the language used within a group (dc:language API3 to retrieve user information and then translates it into and lingvoj:Lingvo). RDF. 3. DEFERENCABLE URIS 2. USED VOCABULARIES Each exported people, user, and group is assigned a spe- The exporter mainly uses the following vocabularies and cific non-informative resource URI. Each URI is deferenca- reference datasets to export user accounts: ble, and uses content-negociation principles to redirect ei- ther to the Flickr.com user page if browsed with an HTML • FOAF - as a standard vocabulary to model people browser, or to the RDF file that contains all the statements and their relationships, FOAF is used to represent the about the user, account or group if browsed with an RDF owner of a Flickr account (foaf:Person), his proper- browser. Those redirection use 303 and 200 HTTP codes 1 http://apassant.net/home/2007/12/flickrdf/ to be compliant with Semantic Web URI principles [5]. Yet, 2 http://phpflickr.com/ URI of the ImageGallery instance is the same as the URL of 3 http://www.flickr.com/services/api/ the gallery webpage, since it is identified as an informative resource. 4. LINKING TO A FLICKR PROFILE Reusing Linked Data principles[2], a good way for any- one to interlink his own FOAF profile to his foaf:Person 4 http://rdfs.org/sioc/types 5 http://geonames.org 6 Copyright is held by the author/owner(s). http://ws.geonames.org 7 LDOW2008, April 22, 2008, Beijing, China. http://lingvoj.org Figure 2: Interlinked social networks representation the old one to be removed), since there is not direct way for the script to be informed of Flickr users changes at the moment. Figure 1: Browsing a Flickr profile in Tabulator 7. RELATED WORK Different wrappers to create RDF data from existing sources have been mentioned in this paper. Other exporters may in- URI created with the exporter is to combine the use of clude the AudioScrobller wrapper13 or OpenLink Virtuoso owl:sameAs and rdfs:seeAlso. Thus, a person that already sponger14 , a more generic way to extract RDF data from has a FOAF URI can identify himsemlf as the same than non-RDF sources. However, there is not yet agreement on the one described by another URI in a Flickr profile. It how to export such data and to combine vocabularies. This also allows tools supporting OWL inference to make such demo may be used as a basis for best practices to do so. identification when querying various sets of RDF data. Finally, regarding Flickr, the Flickcurl API15 provides a Moreover, in case the user do not have any existing FOAF way, among various operations, to get RDF triples from any profile, this script gives him a URI (and a profile) that Flickr picture. A script to interlink this data and the cur- he can the reuse in other Semantic Web applications like rently described exporter may be available in the future. Revyu.com8 to be uniquely identified in the Semantic Web. 8. NOTICE 5. BROWSING AND REUSING DATA The work described here is personal work, and is not af- Created data can be used as any RDF data, for exem- filiated with Flickr.com in any way. ple browsed with the Tabulator9 extension for Firefox, as shown on Fig.1. Moreover, people can use SPARQL to run query over the data, either on the fly or by crawling it, and 9. REFERENCES in case they already have RDF data exported from services [1] S. Auer, C. Bizer, G. Kobilarov, J. Lehmann, like Twitter10 or Facebook11 , may merge them and query or R. Cyganiak, and Z. Ives. DBpedia: A Nucleus for a view their complete open and machine-readable social net- Web of Open Data. 6th International Semantic Web work in a uniform manner. Fig.2 displays the output of a Conference, November 2007. simple script12 that queries a FOAF profile to retrieve all [2] C. Bizer, R. Cyganiak, and T. Heath. How to Publish owl:sameAs URIs and related RDF documents for a given Linked Data on the Web. http://sites.wiwiss.fu- user to find all his relationships from different social net- berlin.de/suhl/bizer/pub/LinkedDataTutorial/, works. It provides a simple but efficient use-case to see how November 2007. Semantic Web technologies can achieve the goals of social [3] J. Breslin, A. Harth, U. Bojars, and S. Decker. Towards network and data portability. Semantically-Interlinked Online Communities. 2nd European Semantic Web Conference, May 2005. [4] D. Brickley and L. Miller. FOAF Vocabulary 6. PRIVACY Specification 0.91, November 2007. In order to respect the Flickr API terms of use and user http://xmlns.com/foaf/0.1/. privacy, only publicy available data can be exported. Yet, [5] L. Sauermann, R. Cyganiak, M. Völkel, and D. Ayers. in case a user switch his profile from private to public, he Cool URIs for the Semantic Web. currently must recreate his exported profile (in case he wants http://www.w3.org/TR/2007/WD-cooluris-20071217/, 8 http://revyu.com December 2007. 9 13 http://dig.csail.mit.edu/2007/tab/tabtutorial.html http://dbtune.org/last-fm/ 10 14 http://sioc-project.org/node/262 http://www.openlinksw.com/virtuoso/Whitepapers/html/ 11 http://www.dcs.shef.ac.uk/ mrowe/foafgenerator.html VirtSpongerWhitePaper.html 12 15 http://apassant.net/home/2008/01/foafgear http://librdf.org/flickcurl/