I'd still like to point out that no other game in existance requires this, nor does any other subscription/log-in service like Paypal/eBay! Seems like overkill to me over one game
The techniques people are using to hack accounts on Diablo III would work just as well for Paypal, eBay, or your online banking website (assuming you could identify a website Paypal users go to all the time that you could put a keylogger on). In fact, I'm pretty sure people get Paypal and eBay phishing emails all the time. Blizzard's security is just as good if not better than any of those (well, except for the case-insensitive passwords, cmon Blizzard what decade is this).
The problem with Blizzard is:
* The stuff on a battle.net account is easily fungible, unlike most other online games...
* ...but it's also not a serious crime and will not get Interpol down on your ass like hacking a bank....
* ...and it's very easy to identify or create websites a Diablo III player might visit and/or things they might download. Much harder for Bank of America members. (Well, I guess buying some ad space on the Consumer Protection Agency's website might garner a few likely bank accounts.)