The worst part of such fragmentation is the "fiefdoms" that can often form. We see this at Stack Overflow, we see it at reddit, and even at Wikipedia to some e

The worst part of such fragmentation is the "fiefdoms" that can often form. We see this at Stack Overflow, we see it at reddit, and even at Wikipedia to some extent. A relatively small number of users end up as moderators of one form or another, and can exert disproportionately more control over other, non-moderator users. While this may not necessarily be a bad thing in terms of maintaining a certain minimum standard of quality, it does take responsible moderators for this to happen. More often than not, we see people with very little power or influence in the real world using their moderation abilities on some online forum to try to compensate. They use their power just for the sake of using it, and perhaps for the emotional high it may bring them, rather than out of a sense of bettering the community. I think that this kind of behavior is far more harmful than the fragmentation itself.