This won't affect our email at all since we already use mail forwards for everything.
They do have the option of 5 fixed IP's (they call them "persistent" IP's) and a 384 connection, an interesting option should I want to have a server again. At the moment I'm using no-ip.com for everything, but if I actually had IP's - other choices present themselves.
Unless comcast totally sucks. I don't know anything about them yet.