I doubt it. I'd like to see evidence that posting patterns can efficiently estimate the interest of a message (besides spam, of course). I wonder what you have in mind with "playing ping-pong". A long exchange between two people can be interesting, or not. The proposal already suggests a [potentially] good way to estimate the interest, I don't see why we'd need such heuristics too.Just to add to the brainstorm, an incremental counter measuring how many emails one person sent to the list in a 24-h window could be very useful to directly ignore people when they start to play ping-pong.