Diabloii.net is reporting that "reliable inside industry sources" have confirmed that Diablo 3 is the big announcement that will come at WWI on Saturday.
Since Diabloii didn't say that the sources were at Blizzard, I'm skeptical and I still consider it a rumor, not a confirmation. I'm always skeptical of unnamed sources anyway, but in this case, with the secrecy surrounding the announcement and the legal actions coming against other Blizzard ventures, I'm especially dubious. If anyone at Blizzard leaked this information, they'd be found out and fired for sure. If it wasn't someone from Blizzard but rather someone else in the game industry, I wouldn't take what they say with a grain of salt. However, on the chance that this information is correct -- and Diabloii is asserting that it is -- we want to offer it to you so you can make up your own minds.