Expressing Argumentative Discussions in Social Media Sites Christoph Lange 1,2 , Uldis Boj¯ ars 2 , Tudor Groza 2 , John G. Breslin 2 , and Siegfried Handschuh 2 1 Computer Science, Jacobs University Bremen ch.lange@jacobs-university.de 2 DERI, National University of Ireland, Galway, IDA Business Park, Lower Dangan, Galway, Ireland {uldis.bojars, tudor.groza, john.breslin, siegfried.handschuh}@deri.org http://www.deri.ie/ Abstract. Among the activities that people participate in on the Social Web are argumentative discussions and decision making. This paper analyzes a series of use-cases (from the perspective of social media sites) that share the presence of such argumentative discussions and where the structure of online discussions can be represented in SIOC. Our goal is to externalize implicit argumentation structures hidden in the user- generated content. For capturing it and making it explicit, we propose a SIOC Argumentation ontology module as a formal representation. 1 Introduction Argumentation can be found and captured in a variety of fields ranging from scientific publications to ontology engineering or agent interaction. Social media sites, which represent the hype of the moment, also host argumentative discussions between their members. Such an interactive argumentative discussion usually starts with an initial proposition stated by a single creator. This is then followed by supporting propositions or counter-propositions from other contributors. The actual semantics, both of the interactivity and the argumentation side of the discussion, is hidden in the structure and content created by the participants, and therefore it is difficult to leverage for use by machines. A possible solution for the first part of the problem is represented by the SIOC initiative (Semantically Interlinked Online Communities) [3]. SIOC aims at integrating online community information, by representing rich data from the social web in RDF. Lately, SIOC became a standard way for expressing user-generated content from social media sites, thus being able to capture their dynamic aspect (interactivity), by modeling the underlying structure of the content. In addition, when complemented with other commonly used vocabularies (like FOAF 3 ), SIOC enables innovative ways of expressing personal profiles and social networking information. 3 http://www.foaf-project.org/