CNET has an interesting reprint from the NT Times on "click fraud", where you click on an ad in a website with no intention of really buying, or even viewing the website.

It is nearly impossible to pin down precisely how widespread click fraud has become. John Squire, the vice president for product marketing for Coremetrics, which provides consulting and Web analysis for online merchants like Eddie Bauer, OfficeMax and CompUSA, estimated that his company's clients are spending approximately $10 million a year on fraudulent clicks. That is, they are spending about $10 million on consumers that don't exists

That's $10 million dollars in penalty for sticking ads in my face, especially popups.

So if you have a moment, feel free to click on some of those ads, and ring up the bill for the advertiser. Then just don't by the junk they're advertising.

If it's stuff you wouldn't want anyway, you have the bonus of confounding the people who are compiling marketing information on you, by giving them bogus data.

Seems like fun to me.