FWIW, if I'm doing an obviously commercial query - usually comparison shopping or looking for local businesses or professional services - I click on the ads all the time. It's like having hand-curated search results where each curator has an incentive to put their best foot forwards.
The curator always has a bias, usually a strong bias. At least when it's labeled as an Ad, you know the bias exists and can account for it by visiting multiple sites. The only way to solve bias issues is to get many contrasting viewpoints so you can decide for yourself what the reality is.
I usually have both the query and query + [reviews] open in separate tabs. Either that, or just the reviews query, because that usually surfaces enough ads that I can click through all the major players myself.
I'm rarely looking for a search result that takes me to a place to spend money either, but when I'm not I usually don't get ads either. Check out [jquery touch] or [haskell ffi] or even [gabby douglas] and [us open]. No ads on any of them.
