Only once for me on Amethyst.

Once does the trick on Amethyst.

Dunno. Snort Social and Satellite Earth don't seem to have any block or mute functions at all.

Not going to be installing phone-apps for this thing since I never want to use it on my phone, phone has tiny screen and crappy keyboard.

If it won't work in a browser I don't want it, so perhaps that's limiting my options for a good mute.