User blog comment:Aokpisze/Timeline of the MB's, 2009-Present/@comment-3003185-20120516203248/@comment-4052371-20120517202344

Actually, removing the duplicate topic rule would slow down moderation since the mods would have to check all the topics in a forum to see if it wasn't a dupe. (And considering how large the MBs have gotten, this makes the problem even worse.) And mod parties are not all that good. People always naturally try to take advantage of the faster moderation while it lasts, to spam like crazy and raise their post count.