Really? I'm gonna say that posting pics of your butt on non-porn forums is gonna get you booted from most of them, likewise if you post spam or contraband media. Even on social media where no moderation facilities exist, if one or a few participants are serially abusing the channel and can't be persuaded to stop or leave, the other users will tend to set up a new channel that doesn't include those bad actors and be more careful about who they invite in future.