Social network analysis on the semantic web: Techniques and challenges for visualizing FOAF

Abstract

The Semantic Web promises to provide new applications for Internet users through the use of RDF metadata attached to various information resources on the Web. Yet it is somewhat unclear who will provide the metadata, or what will motivate people to provide it, let alone the exact nature of the applications the Semantic Web will ultimately support. What will the "killer app" of the Semantic Web be, and what shape will it take? An answer to this question may have already arisen, in the form of the Friend-of-a-Friend (FOAF) vocabulary. The FOAF project was begun in 1999 to explore the application of Semantic Web technologies (RDF/XML) to describing people's personal details: their professional and personal lives, their friends, interests, and other social dispositions. Its main product is the FOAF vocabulary, an RDF/XML namespacewith elements defined for describing an individual's social sphere (Brickley and Miller, 2003). Recently the FOAF vocabulary has been adopted by many large Web-logging ("blogging") and social networking software sites, such as LiveDoor, LiveJournal, and others.Weblogs, a recent Internet phenomenon, are diary-like sites usually consisting of entries in reverse-chronological order.Herring, et al. (2004) situateWeblogs as a genre bridging between extant media technologies and new forms of computermediated communication. The contribution ofWeblogs to the SemanticWeb comes from the design of the supporting software to automatically generate RDF/XML files including RSS feeds, and now FOAF. The popularity ofWeblog hosting sites, and their ability to automatically generate RDF, has had a large impact on the Semantic Web. Swoogle (swoogle.umbc.edu), at present the largest fully automatic SemanticWeb document aggregator, currently lists 19 large Web-logging sites in its top-50 index of sites with Semantic Web content (LiveDoor is top-ranked with 9,473 documents in Swoogle and LiveJournal second with 7,690), and collectively blogging sites are responsible for 45% of the Semantic Web documents collected by Swoogle. Even from these sites, Swoogle crawls only a small fraction of the available FOAF documents: LiveJournal automatically generates FOAF files for each of its 6.7 million users, several times more than the number of documents in Swoogle.