A number of Diablo III players have claimed that they have logged into their accounts and found that they have been hacked. Players claim that their gear, characters, and gold vanished without a trace. Blizzard Entertainment says that it is taking these reports "very seriously" and is looking to what exactly is going on. Other reports have indicated that this was being caused by some sort of bug.
"Historically, the release of a new game - such as a World of Warcraft Expansion - will result in an increase in reports of individual account compromises, and that's exactly what we're seeing now with Diablo III," Community Manager Lylirra said on the community boards. "We know how frustrating it can be to become the victim of account theft, and as always, we're dedicated to doing everything we can to help our players keep their Battle.net accounts safe."
One thing that many players are finding to be frustrating is that Blizzard's authenticators haven't protected their accounts. The authenticators are supposed to add an extra layer of security via a phone number or through iPhone and Android apps. The authenticator works by generating a unique code tied to your account that expires within two minutes every time a user tries to log in.
Blizzard rejects the idea that the authenticator isn't working:
"We've been taking the situation extremely seriously from the start, and have done everything possible to verify how and in what circumstances these compromises are occurring," said Blizzard community manager Bashiok. "Despite the claims and theories being made, we have yet to find any situations in which a person's account was not compromised through traditional means of someone else logging into their account through the use of their password. While the authenticator isn't a 100% guarantee of account security, we have yet to investigate a compromise report in which an authenticator was attached beforehand."
If you have had your account hacked, IGN has some advice to help you deal with the situation here.
Source: IGN by way of Andrew Eisen.