I'm bummed it doesn't work on websites, I guess I'm a nerd so not the target audience, but I use the mobile web versions of twitter and reddit because I don't want to give the app developers more permission than they have,but I apparently can't block the safari app (I don't need more fine grained blocking than this). I guess apple is probably making this impossible, but it's still a bummer.

Also, would it be a ton of work to get a firefox extension?

Cool concept, I hope it eventually meets my needs. I have the game I compulsively play blocked at least.