Recently, web collaboration (also known as crowd sourcing) has started to emerge as a viable alternative for building the large resources that are needed to build and evaluate NLP systems. In this spirit, the Anawiki project (http://anawiki.essex.ac.uk/) [8] aimed at experimenting with Web collaboration and human computation as a solution to the problem of creating large-scale linguistically annotated corpora. So far, the main initiative of the project has been Phrase Detectives (PD) [2], a game designed to collect judgments about anaphoric annotations. To our knowledge, Phrase Detectives was the first attempt to exploit the effort of Web volunteers to annotate corpora (subsequent efforts include [1] and [5]).