This isn't hacking. People are all wigged out about this guy "hacking" peoples' accounts. There are no viruses, no trojans, no "hacking" in the way media has popularized it. He's doing this through social engineering. He figures out enough information to convince Blizzard phone support that he is the actual account holder and gets phone support to change information to his favor and allows him access to the target account. There's a simple way to stop anyone else from being compromised - delete everyone you don't know PERSONALLY or anyone you might not be able to trust from RealID and add them to BattleTag instead. Don't give out your name, email address or any other personally identifiable information. I can assure you that neither him nor any other "hacker" is gaining access to Blizzard servers via an exploit or other explicit means. If that were the case, this would be a HUGE problem that Blizzard would have fixed in hours.