I tried "sun hats" and got the ad from coolibar and only one other result out of ten on the first page. So, I ask for some more facts, not just anecdotal evidence of failure. Do you visit coolibar regularly? were you logged in or incognito? I tried both and got similar results. How many searches did you perform to come up with these anomalies? Have you seen this behavior before or perhaps it was just a bug?

UPDATE: It appears we have been spammed. To answer my own question, I think he has been on coolibar. This person is launching a site that is a directory for hats (first link above blog post). His lack of any response says it all. Clever ploy ...