It's been known that Blizzard were working on a new MMO for some time now and more information was divulged on the project at this year's Blizzcon.
The good news for World of Warcraft players is that Mike Morhaime, the president of Blizzard believes that both MMOs can exist at the same time.
"We are working on a second MMO. We're thinking of it as sort of a next-generation MMO. It's not a sequel to World of Warcraft - we want to do something a bit different," said Morhaime when speaking to GameTrailers.
"We're not trying to replace World of Warcraft. We think that World of Warcraft can continue co-existing with our new MMO and some people might prefer the new one, some people might still prefer to play World of Warcraft."
New information about the project isn't expected until at least 2012.