Display networks are simply great, and in many cases much less competitive than search results for placing ads. I find myself clicking on many contextual placements which are right spot on with the topic in discussion on a web page, more often than on an ad in the search results. Actually I've become blind to the search ads somewhat!
Keep in mind that you pay per click, so try to filter out the non-buying visitor by including terms related to buying like "Buy Now", "Huge Discounts", "Offers End Soon" etc. into the call to action.
Yes, we all would like to deliver information to the one who seeks just that, but when it comes to PPC advertising, ROI definitely counts.