The best advertisements have

    display:none;

no but seriously, the whole idea of adverts is to "push" you to buy things you don't need, so how could they ever be good?

Also the general idea of selling my website visitors eyeballs to a third party is very difficult to swallow for me. If I run a content website and I put adverts on it, selling to the highest bidder, what respect to I have for my readers?