Smart tools to easily discover and query decentralized Semantic Web data Alexandre Passant 1 and Uldis Boj¯ ars 2 and Frederick Giasson 3 and John Breslin 2 1 Universit Paris IV Sorbonne, Laboratoire LaLICC, Paris, France alexandre.passant@paris4.sorbonne.fr 2 Digital Enterprise Research Institute, National University of Ireland, Galway [uldis.bojars, john.breslin]@deri.org 3 Zitgist LLC., Quebec City, Canada fred@fgiasson.com Abstract. Even if more and more RDF data are available on the Semantic Web, finding and querying it is still difficult due to its decentralized nature. In this demo, we will detail a distributed architecture involving different scripts that interact with each other to help finding and querying such data, with emphasis on user participation and intuitive user interfaces. Key com- ponents of this architecture are the Semantic Radar used for discovery of Semantic Web data, Ping The Semantic Web service for aggregating loca- tions of RDF data and users of RDF data such as doap:store. 1 Introduction As the Semantic Web meme is spreading on the Web more and more people publish RDF data, from bloggers and bulletin boards making their data available with SIOC[1] to open-source software developers using DOAP 4 to describe their projects. Some of the existing tools offer functionality to browse this data and to navigate through the Semantic Web, and search services such as Swoogle[2] try to help find RDF documents but it is still a difficult task because of the decentralized nature and relatively low concentration of these documents on the web. We have implemented an architecture involving scripts with easy-to-use inter- faces enabling us to (1) discover decentralized Semantic Web documents; (2) main- tain an up-to-date database of URIs of these documents thanks to user participation, and (3) allow external services to use this architecture to find RDF data and offer user-friendly browser and query interfaces. 2 Architecture of the system Based on a distributed architecture, our system involves the following components (see Fig. 1): – Data sources – RDF documents spread around the Semantic Web, created by people themselves or by the applications they are using such as SIOC exporters 5 ; – Semantic Radar 6 – a Firefox plugin that allows anyone to be part of the col- laborative discovery of Semantic Web documents by simply browsing the Web, using autodiscovery links to find RDF data on the Web. – Ping The Semantic Web 7 (PTSW) – a webservice that maintains a list of RDF documents it recieves pings about, from the Semantic Radar and other services; 4 http://usefulinc.com/doap 5 http://sioc-project.org/exporters 6 http://sioc-project.org/firefox 7 http://pingthesemanticweb.com