The XKCD folks implemented what they call "Robot9000". Robot9000 attempts to ensure that every comment being added to a site or chat channel is unique when comp

The XKCD folks implemented what they call "Robot9000". Robot9000 attempts to ensure that every comment being added to a site or chat channel is unique when compared against the history of the channel. It basically hashes a somewhat stripped-down version of each comment and compares it against the entire historical corpus of their chat. If the comment is found then the user is muted for an exponentially-increasing amount of time for each infraction. I believe there's a slow decay on the mute duration as well. This sort of filter won't stop stupid text, but it seems to be working for them. It's a novel approach to the problem of signal-dilution as a social network grows. Robot9000 release announcement: http://blag.xkcd.com/2008/01/14/robot9000-and-xkcd-signal-attacking-noise-in-chat/ http://blag.xkcd.com/2008/01/14/robot9000-and-xkcd-signal-at... Perl source: http://media.peeron.com/tmp/ROBOT9000.html http://media.peeron.com/tmp/ROBOT9000.html