The latest version of the Opera Web browser has a spectacular feature: you can tell it to reject pop-up windows. No more X10 ads. No more popups telling me I'm viewing a Tripod member site. No more malicious ad windows which spawn multiple copies of themselves when you try to close them. Hurrah!
The downside is that Opera makes no differentiation between those popups and (for example) the popups you get when you click on a comment link on many weblogs. Which of course makes sense, because a JavaScript onClick code could easily pop up an ad at the same time it pops up a comment window, so there's really no way for Opera to know which windows are the ones you want, and which ones aren't. Fortunately, it only takes two keystrokes to turn the feature on or off.