Last year iPhone users were downloading so much stuff, that AT&T suffered several massive data network outages. So it’s only fair that GigaOM wonders whether the stress of all those 3G Youtube downloads will once again bring AT&T to its knees.

My guess? Yes, but only localized. There are places in the country where it’s almost a crime to not carry an iPhone (Yes Bay Area, I’m talking about you). When the combination of disposable income and pure Apple love meet, there are bound to be thousands of people rushing to trade in their old iPhone for a new one. If past experiences are any indication, then AT&T will have 2 weak spots: their activation systems and their network.

Last time, people were able to activate their iPhone at home, sitting at their desks with a cup of apple juice. This time, you’ll need an Apple or AT&T store, and the entire process will take at least 10 minutes per customer. That is not a good time to see the AT&T computers choke (again).

Time will tell, but I’d say the weeks after July 11th won’t be full of good PR for AT&T.