We've been having a sock-puppet attack on the GameDev Stack Exchange site over the last few days. I am not fully aware of the details but there seem to be two exploits being used:
First - the threshold for flagging comments and having them auto-delete seems to be way too low. With enough accounts - this guy seems to be able to delete other people's comments at-will. (Including comments by people with vastly more rep.)
GDSE mod Tetrad tells me that the tools for detecting and reversing this are very limited. I think there needs to be some kind of counter-balance to the automatic deletion. Either a higher threshold, or a easier way to restore comments after an attack like this.
His latest tactic for using this is as follows: He deletes a bunch of comments, then, using the same username as an existing user, posts a fake screenshot of the comments with people saying inflammatory things. He then deletes any comments that point out that the screenshot or his account is fake.
Second - the guy seems to be able to rapidly recreate accounts on the GDSE, from the same original SO account as its "base" account, giving him an account with 100 bonus starting rep.
This is particularly impacting GDSE at the moment, as we're currently holding moderator elections over there. This guy's doing everything he can do attack one of the candidates.