New rule: If a member of a guild says "lol", "brb", or something else that's disruptive to the roleplaying experience during an auction, the guild will receive one warning. If a member of that guild offends again, the guild will be barred (dismissed, banned) from the auction.
Comments? I'm not sure this is the best way to address the problem, but it seems like an obvious one. I encourage people to think of creative solutions and post them, since this kind of behaviour has apparently annoyed quite a few people.