Ads drive me crazy, too. But Madison Avenue knows they work, at least to a point . . .
The big thing in marketing is synergy. I find it very distracting when I want to just view a store's web site, and all these stupid ads pop up from "other" retailers, service companies, etc. on the top, bottom or sides of the web page I'm viewing. The ads have nothing at all to do with (for example, if I'm looking at dresses online), and may include ads for kitchen appliances, cars, vacations or even dating sites. All of it turns me off, and I refuse to ever click on those.
I don't mind ads on this WDW Magic forum, however, as it helps to support the forum and the great work of Steve and his moderators. That's different. So I just wanted to make the distinction between ads that I find acceptable (those on here) and those that are just nuisances on retailer's (and other) web sites.