I have nothing whatsoever to do with mydomain.com, but was following the festivities last night (sort of along the lines of watching a car wreck :).
My impression is that they have four name servers, three in Seattle and one in the East. The eastern one wasn't directly affected, but folded under the load when all the DNS traffic started going to it.
Their explanation doesn't quite work, since they don't say how the ended up with ACS errors at their site (and if I recall correctly there were even some ACS install messages at one point). The only thing I can guess is that the load from the DOS attack caused their MySQL database (I think that's what I read it was) to eat it's shorts, and they had to restore everything.
Obviously not an "enterprise class" operation - but hey, it's free, so IMHO no-one should have expected any more.
