Oh give me a break. I'm a member of several forums that give normal members a PM allowance of 1000, and they have three times the members and no performance issues. While 1000 may be a bit extreme, the point is a few extra PMs per member is not going to affect much. I'd say they are pretty much all less than 100kb, some shorter ones probably 10-20kb. Big deal. If the server can handle all the short, pointless posts people post here every day, it can handle a few messages.