The difference between comcast and AT&T "internet wise" is the megabytes. Comcast uses broadband and may offer more MBS then AT&T. AT&T is a DSL service.
For example if BroadBand speed is 12mbs then Dsl is maybe 9mbs.
But when you're on broadband connections and theres a bunch of people...
Well If you have gmail and you download google chrome, convert your fav's to that browser. So when you download that browsers to your new computer, all you have to do is log in to your account and vola!!!!! If not just save your Favs to a jump drive..............