A simple idea: ability to recall the last twenty or so messages on cabal/clan channels (this wouldn't be very stressful for the server, since there's a limited amount of those) and, if possible, for tells.
For tells, logoffs might as well clear those, if necessary. For cabals/clans, an elder/leader could possibly enable/disable this function if speaking behind people's backs is the thing for that particular organization (and they're too lazy to spam out such from the channel, or to use tells/says).
