There aren't any general rules, since I was hoping to not have to force any rules, but generally I'll ask for someone to slow down on the bumping if they bump way too often. Example: "up" @ 3:54PM and again @ 4:24PM .. previous day: "up" @ 8:43PM, 9:37PM, 10:23PM, 11:02PM. These forums aren't all that busy that a bump is required that often, IMO.