That may be true in general, but if their search is for "how to avoid over-exposing a negative" or something like that, they are not searching for a book, equipment, or supplies. They are looking for an answer to a specific technical question.
So please don't take my analogy too literally. I'm trying to get at the fact that the people coming to the OP's site are apparently not "in the market" for a product or service, because no amount of tweaking or repositioning of ads changes their reaction to them, which is to ignore them.
While my analogy may have its limits, my advice still stands--he should consider building his content in new directions.