During my PhD work here at DAI-Labor, we developed a prototype of a social search engine called SPREE. SPREE is intended as an online community where every user shares his knowledge and benefits from the knowledge of other users alike. To this purpose, the system automatically channels user questions to the most qualified experts. Techniques involved during the expert identification process include natural language processing as well as a tfidf based hierarchical classification of questions to a given knowledge taxonomy. The algorithms are described in our SPREE paper.

The prototype was written in Python using the Turbgears framework on the server side and a combination of Dojo/Mochikit for most javascript (AJAX) related stuff. It was much fun using Python/Turbogears for rapid prototyping after years of Java development.

You can register to SPREE at http://www.askspree.de. Let me know how you like it.