I have two email addresses that I check continuously throughout the day and I don’t think they’ve both been working at the same time for more than 5 minutes a row today.
I sent a complaint in to Dreamhost tech support and this was the answer (at 5:02 pm eastern):
Sorry for the trouble. We’re currently working on re-initializing the mail server your account uses. We plan to have it running again within a couple of hours. We are currently working on implementing a new 64-bit mail system that will avoid the problems we’ve been having with mail lately.