there are guys pushing a few hundred thousand dollars worth of offers a day. It's a huge huge industry, but you can't just toss up some banners and expect to profit.
Do you then mean that affiliate ads are not quite suitable for an informative website and do not quite compare or supplement adsense. I suppose I mean to ask, do you mean affiliate ads are fundamentally different from adsense, in the way that say walking and driving a car are different.
Yeah, most successful affiliate marketers seem to do it as their main thing--- they build entire sites with the sole purpose of pulling in visitors who'll click through and buy something via the affiliate link. It seems much more difficult to use them as a way to make money from a normal site, although I've had modest success with relevant Amazon links (Amazon is nice because you get commission if someone clicks through and buys anything within 24 hours, not necessarily the product you linked).