hannamyluv - 1:29 pm on Sep 17, 2008 (gmt 0)
I personally know a Google human evaluator. She is given a query and a page. She is asked to rate how closely the page matched the given query. I would assume that the page was one that came up in the results, but as it was presented to her, this was not the case. She got a phrase and a page and was asked to judge how well the page matched the phrase.