The original article on Gawker on this was horrible. They completely spinned it to sound like Apple was at fault. Only in one little phrase did they happen to mention that AT&T was at fault. They really screwed themselves over by stealing the iPhone, and now they're fighting back by writing mean blog posts. Cute.
Yeah, I've notice that ever since they were denied a press pass to WWDC, Gizmodo has been piling on some Apple hate. Before the WWDC snub, I think it's fair to say they were pro-Apple. Ever since WWDC, there's been more anti-Apple stories written, and there are little one-line cheapshots in some of the more 'unbiased' stories. I've gotten sick of Gizmodo/Gawker's childish behavior and have been sticking to other tech sites now.
It's not a leak if it's just email addresses. Email is useless if it's not public. If you get spam or unwanted messages, then set some filters. If you can't even do that, you probably shouldn't be using email. If you can't ignore things like that, you're probably better of not using the Internet.
If email addresses are a leak, then I guess that makes the phone book a disaster. Real names matched to addresses and phone numbers, oh my!
It's vaguely possible that some email name schemes could reveal something of an organizational structure that could be of some sort of value to someone. You'd be able to get multiple addresses from the same org, most likely.
But that would indicate security flaws with the naming scheme as much as anything else.