Er, actually, it wasn't an email, but it was posted to their status page:

http://www.dreamhoststatus.com/2007/10/17/policy-clarification-personal-storage-back-ups/

Something tells me that if someone was actually using their site to serve the amount of data they give you with their plans, they wouldn't exactly allow it. Network backup is an obvious benefit of Dreamhost, and, at this point, the only one, now that my $10/year pricing has expired and I'm on the hook for $10/mo.