It seems that just this week Blizzard have projectblackstone.com the domain projectblackstone.com. It currently doesn’t resolve but it’s only been alive a couple of days so it is still early days. We can’t tell from that what the title is but they often have code names for things they are working on. Project Titan for the ongoing MMO and Diablo 3 was nicknamed Hydra – actually in retrospect that one is more obvious.
The full name only crops up in one of their titles that I know of and that’s World of Warcraft. There is a ring, an NPC and a bridge that bear the name Blackstone. So is it another expansion pack for WoW? There is the Black Soulstone in Diablo 3 which is a looser connection but still, could it be the expansion pack for us? Or even looser is their very old platform title Blackthorn. Or is it something entirely different?