The Crowdsourcing Track has a new URL

The National Institute of Standards and Technology (NIST) Text REtrieval Conference (TREC) Crowdsourcing Track investigates use of crowdsourcing for evaluating relevance of search results.  The track ran for the first time in 2011 and will run again in 2012.

The Track page has moved to: https://sites.google.com/site/treccrowd