[eggnet]

Signal to noise ratio. When the admin of a server thinks the ratio of another server is too low, the admin will block it.

What's the definition of too low? Up to the admins of that server.

[cubefox]

That's the problem. It's enough when people choose themselves whom to follow.

[eggnet]

It's not enough if those people's posts are flooded with low quality replies.

[cubefox]

That seems to be only a problem for a few people with a very high follower count or for viral tweets. Both are quite rare relatively speaking.