When comments exceed 20
What is the
More than 20 comments posted flag? Is it automatic or do people somehow set this flag?
What causes it, and why is having more than 20 comments bad?
I was wondering the same thing, and my conclusion (absolutely baseless actually) was that it's not necessarily bad, but it could be a sign of flames going on in there, and thus the flag. Just a mark to get some attention and perhaps do some cleaning if required.
It is set automatically when a post has more than 20 comments posted. A large number of comments often indicates that a discussion that would be better fit for chat is taking place in the comment space.