Very good AdBlocker :)

MUST HAVE BROWSER ADD-ON!

Seriously, this add-on is amazing. It's the swiss army knife of Firefox add-ons. It blocks ads, trackers, malware, spam, scams, annoyances, etc. You can configure it to do whatever you want, whether you are an advanced user, or if you're just a basic user, the default options will do fine.

It's easily the best ad blocker and content blocker overall that I've used. It's easy on resources, super easy to turn on and off, and gets the job done. I think everyone should have this extension honestly. Once you get it, there's no going back.

Addon fails to block ad-videos on most famous streaming-site Twitch.tv, the ad-videos that run before the actual stream-content.