It has immense blocking power. I can block specific ads on any page, but more important is that I can defeat site devices which have been harassing me for using an ad blocker - just run the routine which begins when you click on "Block an ad on this page", follow the prompts, experiment, rinse and repeat a few times until you've isolated the offending item which covers part of your screen, just like when you're blocking a paid ad......Ad-Coders, you're MY beeeeyyytch now!

One thing that would improve this addon is the ability to unblock blocked ads on a page or a site by walking them back just one at a time, instead of having to unblock everything you've blocked, or live with potential errors.

Also, keep in mind that it's an ad blocker, not a popup blocker. While I think there's a version of this addon which does both, I'm using Strict Popup Blocker for that functionality, which I'm happy with.