Harvesting and distributing semantic data: FOAF and Firefox

One of the most attractive aspects of Mozilla Firefox continues to be the incessant supply of useful (and not-so useful) Extensions. The supply is virtually endless, and long may it continue! (What would I do without Zotero, or Firebug?!) We have seen the emergence of some useful metadata tools, such as Dublin Core metadata viewers, and more recently, Semantic Web widgets. Operator is an interesting example of the latter, harnessing microformats and eRDF in a way that allows users to interact easily with some simple semantic data (e.g. via toolbar operations). Another interesting Firefox extension is Semantic Radar.

Semantic Radar is a "semantic metadata detector" for Firefox and is a product of a wider research project based at DERI, National University of Ireland. Semantic Radar can identify the presence of FOAF, DOAP and SIOC data in a webpage (as well as more generic RDF and RDFa data) and will display the relevant icon(s) in the Firefox status bar to alert the user when such data is found. (See screen shot for FOAF example) Clicking the icon(s) enables users to browse the data using an online semantic browser (e.g. FOAF Explorer, SIOC Browser). In short, Semantic Radar parses web pages for RDF auto-discovery links to discover semantic data. A neat tool to have...


Semantic Radar has been available for sometime, but a recent update to the widget means that it is now possible to automatically 'ping' the Ping The Semantic Web website. Ping The Semantic Web (PTSW) is an online service harvesting, storing and distributing RDF documents. If one of those documents is updated, its author can notify PTSW to that effect by pinging it with the URL of the document. This is an amazingly efficient way to disseminate semantic data. It is also an amazingly effective way for crawlers and other software agents to discover and index RDF data on the web. (URLs indexed by PTSW can be re-used by other web services and can also be viewed on the PTSW website (See screenshot of PTSW for my FOAF file)).


It might just be me, but I’m finally getting the sense that the volume of structured data available on the web - and the tools necessary to harness it - are beginning to reach some sort of critical mass. The recent spate of blogs echoing this topic bare testament to that (e.g. [1], [2]). Dare I use such a term, but Web 3.0 definitely feels closer than ever.