Excelente bloqueador de pop-ups (ventanas emergentes). De todos los que probé este fue el mejor.

Excelente, funciona muy bien ^^

This is an absolutely essential add-on for Firefox and honestly I'm surprised it's still not on Mozilla's official Recommended Extensions list yet.
Even with everything on Firefox set to strict I still had a bunch of unwated/intrusive/security-risk popups showing up on various sites, but since getting this add-on I even forgot those exist on the web. It's impressive to say the least. Thanks to whoever made this !

I had no pop-ups sneak by this extension in the wild. When testing it against a controlled environment from a website, it failed only on the drop-down popup. The extension is strange in that is needs Firefox's default pop-up blocker activated but does seem to fortify or add additional rules on top of Firefox's pop-up blocker. Deactivating the browser pop-up setting basically disabled the extension as well. There is no seamless way to add individually to the white or blacklist, only whole domains. Clicking on the yellow notification strip to add to whitelist sends it straight to Firefox whitelist settings. You have to copy & paste into the whitelist or blacklist for individual pop-ups. If you simply want to block pop-ups, it does a good job but needs little polish for features.