PieFed labels bot accounts.

Exactly like NSFW, accounts that properly label themselves are no problem, it's when they remain unlabeled that they cause problems.

PieFed both allows an account to label itself and provides a suite of tools to help mods identify whether an account is likely to be a bot or not - e.g. someone who never comments or votes on anything, but manages to post multiple times per minute (or second?).