Google's EWOQ Search Referral String

Some people are noticing Google referrals from search strings that look like:

https://www.google.com/evaluation/search/rating/task-edit?task=XXXXXX

This comes from Google's http://eval.google.com/ which only available to those part of the "EWOQ group." SearchBistro has a ton of details with demos of it in action named Google Secret Lab, Prelude.

There is some old forum discussion on it at Search Engine Watch Forums.

When I tried accessing one of the referral strings I was prompted with a 403 forbidden code saying:

Forbidden

The user [username]@gmail.com is not a member of EWOQ. Please contact the [email protected] for access.

Forum discussion at Search Engine Watch Forums and Google Blogoscoped Forums.