Only one, and it was or is temporary.
I'm with
@Truck_1_0_1_ here.
As with Twitter, I'll only mute-- or block, which is rarer yet-- if one of two things happens:
1. Someone is constantly pestering me and/or going on a rant which, try as I may, I can't avoid (again, that may be a temporary thing where they need to vent, and I'll come back later)
2. They're being genuinely, consistently nasty, and it's easier to cut one's losses with a permanent mute/block
I tend to be more of the mind that, especially for a message board, it's good to hear divergent opinions, though it's nice if they're articulated with reason (vs. merely stating claims without justification). It's a bit hubristic to think most people are below our time or minds, as if we've all the answers. That said, some absolute tosh is spit online, so I don't blame folks for a mute or two.