The SIOC Project: Semantically-Interlinked OnlineCommunities

Uldis Bojars and Alexandre Passant and John G. Breslin and Stefan DeckerDigital Enterprise Research Institute,

National University of Ireland, Galway, Ireland.Email: [uldis.bojars,alexandre.passant,john.breslin,stefan.decker]@deri.org

Abstract—The SIOC project is aimed at expressing informationabout the structure and content of online community sites andat enabling interoperability on the Social Web using SemanticWeb technologies. In this paper we briefly describe the SIOCproject, introduce the SIOC Core ontology and its modules, anddiscuss some SIOC-based applications in terms of human andagent communication.

I. INTRODUCTION

While new paradigms, tools and web services introducedby the Social Web (such as blogs, wikis, tagging practices)are now widely accepted in both public and scientific com-munities, these tools generally act as independent data silos;hence, interoperability between applications is a complexissue. The SIOC project1 aims at solving this by providinga comprehensive data model (as well as related tools andapplications) based on Semantic Web technologies [1] in orderto represent online communities and their activities in anhomogenous way.

The SIOC project consists of two main parts:• The SIOC Ontology, composed of a Core ontology and

different modules;• A set of applications, for both producing and consuming

SIOC data, constantly evolving based on the user needsand implementations.

II. THE SIOC ONTOLOGY

The SIOC Ontology is composed of a Core ontology and aset of modules, focusing on the ease of integration of SIOCin existing applications by Web developers. With an emphasison standard Semantic Web technologies since its beginning,the whole ontology has been designed using RDF(S)/OWL.A comprehensive overview of the SIOC ontology is providedin [2].

A. SIOC Core Ontology

Main classes and properties in the SIOC ontology2 areshown in Figure 1. While relatively small and simple, thismodel is yet powerful enough to represent the content pro-duced and exchanged within online communities. For instance,a Forum represents a space in which discussion happen (notnecessarily a bulletin board, in spite of its name, but forexample as a weblog), and contains different Posts, written

1http://sioc-project.org2http://rdfs.org/sioc/spec

by Users. The following example then describes that Alicehas created a post in a particular forum (i.e. an area ofdiscussion) and that Bob replied to it — as follows (using theN3 notation - prefixes omitted). In order to represent moreabstract containers (such as a personal information space),more general Container and Space classes can be used.

:post a sioc:Post ;sioc:has_creator :alice ;sioc:has_container :forum ;sioc:has_reply :reply .

:forum a sioc:Forum .:reply a sioc:Post ;sioc:has_creator :bob .

:alice a sioc:User .:bob a sioc:User .

Fig. 1. Main classes and properties in the SIOC ontology.

Other properties and classes exist in the ontology, forinstance properties to represent previous and next versions ofan item, which can be used when representing Wikis.

It is worth noticing that each sioc:User is actuallyrelated to the Agent class (from the FOAF3 — Friend OfA Friend [3] — ontology), and that sioc:User can beconsequently associated with both software agents and humanusers. Hence, SIOC can be used to represent communicationbetween bots on the Social Web (e.g. on IRC using the

3http://foaf-project.org

SIOC-IRClog project4) and then enable a machine-readabledescription of communities of agents interacting together onsocial websites. Moreover, another link between FOAF andSIOC is that the social networking aspect can be representedusing FOAF (by foaf:knows), while SIOC can be used torepresent aspects of relationships inside the community, e.g.a user following another (on microblogging services) can beexpressed by the sioc:follows property.

B. SIOC Modules

Several SIOC modules have been defined to extend theavailable terms and to avoid making the SIOC Core Ontologytoo complex and unreadable. SIOC has 4 ontology modules:Access, Argumentation, Services and Types5.

• the Access module defines simple classes and propertiesregarding the notions of Role and Permission to representaccess rights and permissions in online communitieswebsites;

• the Argument module defines classes and propertiesto represent simple argumentative discussions in onlinecommunities websites.

• the Services module defines classes and properties toreprsent Web services related to online communities (e.g.API endpoint and return format, etc.);

• the Types module defines advanced content-types to beused when defining user-generated content from online-communities. For instance, it includes classes such assioct:BlogPostor sioct:Wiki that respectivelysubclass the sioc:Postand sioc:Forumclasses fromthe Core Ontology;

In addition, one of the recent development of SIOC is amodule defining alignments between SIOC and the SWAN— Semantic Web Applications in Neuromedicine — ontology[4]6, providing a complete model for fine-grained argumenta-tive discussions in online scientific communities.

III. STATUS AND UPDATE OF SIOC

Since the goal of SIOC is to provide interoperability be-tween communities on the Social Web, one way to evaluateits success is to consider its uptake on the Web. To illustratethe amount of SIOC data on the Web, according to thePingTheSemanticWeb (PTSW) service7 on June 2009 therewere 132’475 URIs which contain data described using theSIOC ontology8.

In addition to the uptake in terms of number of documents,SIOC is now widely accepted as a core ontology to describeSocial Web communities using Semantic Web technologies,alongside with FOAF. Hence, the use of SIOC is suggested bythe Yahoo! SearchMonkey developer documentation9 (SIOC

4http://irc.sioc-project.org/about.html5Information about SIOC modules: http://rdfs.org/sioc/spec/#sec-modules6http://rdfs.org/sioc/swan7http://pingthesemanticweb.com8The full amount of SIOC information on the Web is larger than described

here as PTSW indexes only a part of available RDF data.9http://developer.yahoo.com/searchmonkey/smguide/profile vocab.html

data being indexed by SearchMonkey to improve presentationof search results) and by various best practices documentsdescribing data publishing on the Semantic Web such as [5].

Various SIOC-enabled applications have been created10,forming a food-chain (Figure 2) that includes data exportersfor Web 2.0 platforms and services (e.g. Drupal11, WordPress,Flickr, etc.), tools for indexing of distributed data, and browserand visualization applications, allowing users to consumeSIOC data from various sources in an integrated way.

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SIOC ontology is an open data format for

describing structure and content of social

media sites in RDF.

SIOC follows best practices of the

Semantic Web by reusing existing

ontologies: Dublin Core, FOAF, SKOS.

Modularised design allows us to keep the

SIOC Core ontology simple and easy to

understand while ensuring extensibility.

W3C Member Submission of the SIOC

Ontology published in July 2007.

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Applications withNative Storage of

SIOC Data

Bypassing Apps byDirectly MappingRDBMS to SIOC

Add-Ons and Fnsfor Exporting SIOCfrom Existing Apps

SIOC from Semi-Structured Data

or Queryable APIs

SIOC Crawlersand AggregateStorage of Data

Indexers ofSIOC Instancesw/o Full Storage

RDF Browsersand Other Custom

SIOC Explorers

SIOC Detectorsand ClippingApplications

Reuse and Importfor Data Portability

Requirements

Graphical Viz ofDerived SIOC

Networks

C((7%$4./&(2%@II)/0.'/(&1

has_host

has_reply

has_container

User

Role

has_function

Usergroup

has_member

has_scope

has_creator

has_parent

Container

Space

has_space

Item

has_container

subClassOf

subClassOf

subClassOf

Forum

Site

Post

Topic

topic

Fig. 2. The SIOC food-chain

IV. CONCLUSION

In this paper, we briefly introduced the SIOC project, itsgoals and means as well as uptake and services overview. Inparticular, in the context of multi-agent systems and onlinecommunities, an already active fields for several years if weconsider for instance [6], the SIOC ontology could be used toexpress in a unified way information about activities of bothhumans and agents interacting in these communities.

ACKNOWLEDGEMENTS

The work presented in this paper has been funded in part byScience Foundation Ireland under Grant No. SFI/08/CE/I1380(Lıon-2).

REFERENCES

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[2] U. Bojars, J. G. Breslin, V. Peristeras, G. Tummarello, and S. Decker,“Interlinking the Social Web with Semantics,” IEEE Intelligent Systems,vol. 23, no. 3, pp. 29–40, May/June 2008.

[3] D. Brickley and L. Miller, “FOAF Vocabulary Specification,”FOAF Project, Namespace Document 2 Sept 2004, 2004,http://xmlns.com/foaf/0.1/. [Online]. Available: http://xmlns.com/foaf/0.1/

[4] P. Ciccarese, E. Wu, G. Wong, M. Ocana, J. Kinoshita, A. Ruttenberg,and T. Clark, “The SWAN biomedical discourse ontology,” Journal ofBiomedical Informatics, vol. 41, no. 5, pp. 739–751, 2008.

[5] C. Bizer, R. Cyganiak, and T. Heath, “How to Publish Linked Data onthe Web,” Tech. Rep., 2007, http://www4.wiwiss.fu-berlin.de/bizer/pub/LinkedDataTutorial/.

[6] F. Gandon and R. Dieng-Kuntz, “Distributed Artificial Intelligence forDistributed Corporate Knowledge Management,” in CIA 2002 - 6thCooperative Information Agents - Intelligent Agents for the Internet andWeb September. Springer LNAI 2446, pp. 202–217.

10http://rdfs.org/sioc/applications/11http://drupal.org/project/sioc