Fryman - I can verify that. As an experiment, I bid around $150 per click on this one keyword tha wasn't worth a lot, and DID have an advertiser as a top sponsor. I wasn't able to push that advertiser below, and they stayed on the top. Needless to say, even if they had a CTR of 10%, and a cost per click of $7 (which they didn't, neither of the two) I should have still pushed them down. Didn't happen. Adi Friedman TwoBelievers.com Web Holdings.
Does Google check for relevance by crawling your webpage to scan for content? Or is it the text in the ad?