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Semantic Web Interest Group

This is the homepage of W3C's Semantic Web Interest Group (SWIG), previously known as the RDF Interest Group. It provides a public forum to discuss the use and development of the Semantic Web. See the group's charter for details of its role and purpose.

The Semantic Web Interest Group is designed as a forum to support developers and users of Semantic Web technologies (RDF, OWL, SPARQL, etc). The group in particular serves to help developers create vocabularies and applications to support a Web data marketplace combining harvesting, syndication, metadata and Web Service techniques.

Membership of the group is open to all interested parties who accept the group's charter; W3C Membership is not a prerequisite. To join the group, simply join our discussions; there is no formal list of members.

The Interest Group functions primarily through public email lists hosted by W3C. The main list is <> (see archives). Other lists sponsored by the Interest Group include www-rdf-logic, www-rdf-calendar, sparql-dev, and www-annotation. The www-rdf-interest (1999-2005) was previously the main list for the IG.) The Mailing List Administrivia page explains how to join these or other W3C discussion lists.

The mailing lists are used for technical discussions. It is better to avoid discussions on various non-technical subjects, for example on patents and patent applications. If need be, separate mailing lists may be set up at W3C or elsewhere for these.

Task Forces

The SWIG sometimes forms sub-groups to investigate specific topics. Current taskforces (see announcement):

Blogs, Wikis, Directories, Meetups

For some years, the site has provided an aggregation of RDF-related blogs.

W3C also hosts the ESW Wiki; this began in the SWAD-Europe project but was adopted by the wider SWIG community. W3C also now hosts a Semantic Web standards wiki.

The Linked Data LOD community project maintain a wiki list of Common Vocabularies.

Sindice provides a lookup index into a large body of RDF data. This includes a useful inspector utility.

Several members of the SWIG community have been sharing answers to common RDF/SemWeb questions on the SemanticOverflow site.

There are regular local “meetups” in the Semantic Web area around the globe. The search result on the “Meetup” site gives a link to most of those.

24x7 chat: #swig IRC channel

Many in the RDF/SW community make use of Internet Relay Chat (IRC) channels for collaboration, in particular via the FreeNode network (channel #swig for general SWIG discussion). The #swig scratchpad, a link annotation system, is provided by Edd Dumbill. It selectively logs comments made in IRC, via an IRC bot 'dc_swig' (see chump site for details). Complete public logs of the discussions on the #swig channel are also available (in text, html and rdf flavours), thanks to Dave Beckett of ILRT.

Note: IRC discussion should be considered public (insecure, loggable etc). IRC chats are not a formal mechanism for W3C Interest Group communications and discussion; it may be useful to circulate summaries of IRC discussion to the archived RDF IG mailing lists.

IRC Resources: IRC Help,, OpenProjects IRC (please read about freenode: using the network).

Linked Data

The Linking Open Data community project began as an activity of the W3C SWEO group (chartered 2006-2008). The project was inspired by Tim Berners-Lee's 2006 DesignIssues Linked Data note. That Note discussed the importance of URIs for linking RDF, and suggested some improvements to FOAF's hypertext RDF design, which used some pre-RDFCore constructs. The Linked Data community evangelised these improved principles very effectively, leading to a massive increase in the amount of public linked data in the Web.

Increasingly, RDF and Semantic Web technologies show up in the wider world as "Linked Data". Key resources include, the now-famous cloud diagram, DBpedia (an RDF view of Wikipedia) and the public-lod mailing list. See also TimBL's TED talk and Wikipedia's Linked Data entry.

Common shallow ontologies and other topical discussions

The SWIG has looked at various subject areas where "a little semantics goes a long way". Some simple shallow ontologies for concepts shared by many applications can play a very strong role in linking together many applications.

Many of these are discussed in a mixture of email lists, IRC chat, and Wiki.


This topic has been on the subject list of the Interest Group, but it then now moved into a separate W3C Incubator Group. The the GEO XG’s home page for further details. The SWIG "Basic Geo" vocabulary is quite widely used.


Time is the next dimension to consider as property which unites many data systems. See the informal

Relational Databases and RDF

Personal Identity - FOAF

The Friend of a Friend (FOAF) system is one in which people can describe themselves in machine-processable form, including contact details and list of people they know. Several million FOAF files link together across the web.

A W3C Note describing an updated version of vCard in RDF is also available. In 2009 a Social Web incubator group was chartered to explore related issues.

Several SWIG and SocialWeb XG participants have collaborated on the FOAF+SSL work, which combines the use of digital certificate technology with RDF's flexible approach to description. W3C hosts two experimental vocabularies to support this work - cert: and rsa:. At the time of writing these are still under development and have not received formal review in any W3C process. Feedback on the design is welcome, either on the foaf-protocols list or via the Social Web incubator.

The FOAF vocabulary is also accompanied by an experimental 'Web of Trust' vocabulary, designed to support PGP-signing of RDF documents. It has not undergone any formal security review, and discussion on how to progress this work (and converge with X509-based signing) is welcome on the SWIG and FOAF lists.


In June 2010 the UK Government Linked Data project contributed an ontology for describing organizations. This is hosted at W3C thanks to Tim Berners-Lee's involvement, and discussion of the work is welcome on the public-lod and public-egov-ig lists.

Media formats

Web Architecture vocabularies


Other RDF vocabs of unknown status...

Vocabulary Status vocabulary

As we develop RDF vocabularies in a grassroots fashion, it is important to indicate their status. One approach to this problem is to use the Vocabulary Status vocabulary. This was initially developed by members of the SWIG and FOAF communities, and has since 2003 become fairly widely used. It is itself not yet well documented, but an initial draft towards a W3C Note is available. Discussion is welcome in all the usual SWIG fora.

See also the Semantic Web Deployment which takes on specific efforts in this sort of area.


Dan Brickley (Semantic Web Interest Group chair) and Ivan Herman <>, (W3C) Semantic Web Activity Lead and Semantic Web Interest Group Staff Contact

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