September 21 – 26 , 2008, Dagstuhl Seminar 08391

Social Web Communities


Harith Alani (University of Southampton, GB)
Steffen Staab (Universität Koblenz-Landau, DE)
Gerd Stumme (Universität Kassel, DE)

For support, please contact

Dagstuhl Service Team


Dagstuhl Seminar Proceedings DROPS
List of Participants


Blogs, Wikis, and Social Bookmark Tools have rapidly emerged on the Web. The reasons for their immediate success are that people are happy to share information, and that these tools provide an infrastructure for doing so without requiring any specific skills. At the moment, there exists no foundational research for these systems, and they provide only very simple structures for organising knowledge. Individual users create their own structures, but these can currently not be exploited for knowledge sharing. The objective of the seminar was to provide theoretical foundations for upcoming Web 2.0 applications and to investigate further applications that go beyond bookmark- and file-sharing. The main research question can be summarized as follows: How will current and emerging resource sharing systems support users to leverage more knowledge and power from the information they share on Web 2.0 applications? Research areas like Semantic Web, Machine Learning, Information Retrieval, Information Extraction, Social Network Analysis, Natural Language Processing, Library and Information Sciences, and Hypermedia Systems have been working for a while on these questions. In the workshop, researchers from these areas came together to assess the state of the art and to set up a road map describing the next steps towards the next generation of social software.

Topic of the Seminar

Within the last two years, social software on the Web, such as Flickr, Delicious, Bibsonomy, Facebook, etc., has received a tremendous impact with regard to hundred of millions of users. A key factor to the success of social software tools in the Web is their grass-roots approach to sharing of information between users: there are no limitations on the kind of tags users may select. The resulting structures are often called ‘folksonomies’, that is, ‘taxonomies’ created by ‘folks’.

Such systems are also considered to realize aWeb version 2.0. The reason is that the initial use of the Web could be characterized by many users consuming what a comparatively small set of producers had developed, whereas with social software on the Web, everyone becomes a prosumer, i.e. someone who produces and consumes content. The success of this approach is visible with applications like flickr,4, which had approximately 250,000 users in April 2006. In the reference sharing systems CiteULike5 and Connotea,6 researchers and others insert, tag, and recommend scientific references in a shared knowledge space. This indicates a currently ongoing grass-root creation of knowledge spaces on the Web which is closely in line with “the 2010 goals of the European Union of bringing IST applications and services to everyone, every home, every school and to all businesses” .

The reason for the apparent success of the upcoming tools for web cooperation (wikis, blogs, etc.) and resource sharing (social bookmark systems, photo sharing systems, etc.) lies mainly in the fact that no specific skills are needed for publishing and editing. As these systems grow larger, however, the users will feel the need for more structure to better organize their resources and enhance search and retrieval. For instance, approaches for tagging tags, or for bundling them, are currently discussed on the corresponding news groups. We anticipate that resource sharing systems, together with wikis and blogs, are only first appearances of an emerging family of Web 2.0 tools.


  • Artificial Intelligence / Robotics
  • Data Bases / Information Retrieval
  • Multimedia
  • Web
  • Society / HCI
  • Complex Systems


  • Folksonomies
  • Social bookmarking
  • Emergent semantics
  • Social network analysis


In the series Dagstuhl Reports each Dagstuhl Seminar and Dagstuhl Perspectives Workshop is documented. The seminar organizers, in cooperation with the collector, prepare a report that includes contributions from the participants' talks together with a summary of the seminar.


Download overview leaflet (PDF).

Dagstuhl's Impact

Please inform us when a publication was published as a result from your seminar. These publications are listed in the category Dagstuhl's Impact and are presented on a special shelf on the ground floor of the library.


Furthermore, a comprehensive peer-reviewed collection of research papers can be published in the series Dagstuhl Follow-Ups.