Yesterday we started absorbing mydoom instead of bouncing them. In around 24 hours, our main MX server for perl.org/cpan.org absorbed 1.3 GB of mydoom. That's 41083 messages. Or, 1710 an hour. Or, 29 a minute. Or, about one Mydoom every 2 seconds. Ouch!
In addition, we absorbed 354 MB of bounces, in 17394 messages. (One bounce every 5 seconds or so.)
The good news is that things seem to have stabilized. We have the machines configured such that they are no longer pegged to the wall. Occasionally a burst of mail will make them lean a little, but they're handling just fine. Mail is moving at full speed, transiting our system in seconds, instead of minutes or hours.
I hope the flow of mail slows soon - even though we are putting plans in place for more servers - I miss the old days, where you could just run sendmail and have it work.