Next time there's a project like this that's going to
have a big first day spike it'd make sense to do load shedding and
divert peak traffic to a server that says "sorry, we're overloaded,
please come back tomorrow and don't panic because you have until the
end of July to sign up and be on the first release of the list." That
and fix the rDNS and price out some alternatives to Redmond Bloatware,
of course.
...and ask the questions asked here (much!) more than a few hours
prior to the event start/spike.