Used to work well, but sadly has been broken by some recent update to Twitter, and this is seemingly abandoned (hasn't had an update for 3 years now).

Go for the addon by RoyRiver instead - https://addons.mozilla.org/en-GB/firefox/addon/one-click-xtwitter-blocker/ - That one's currently working beautifully.

as some other reviews show, it's just not working anymore and i'm not the only person this is happening to. it probably got screwed up because the website updated. will give a better rating once it's back up

5/13/2024
One Block now no longer works. It has been3 years and there has not been an update to fix this.

Does not work with the new twitter design.
Also why does it need "Access your data for all websites"? Can't it just work for twitter related websites?