Blizzard's Chinese office has leaked a production slate showing Blizzard's projects for the next four years. Heads have already rolled at the office over this, and Blizzard have confirmed that the schedule is genuine, although the dates are not set in stone.
StarCraft 2: Legacy of the Swam
World of WarCraft: Expansion 4
StarCraft 2: Heart of the Void
Diablo 3: Expansion 1
World of WarCraft: Expansion 5
Diablo 3: Expansion 2
The most intriguing title on the list is Titan, Blizzard's new MMO game (though not necessarily an MMORPG). Titan has been in development for a few years already, and if it sticks to its late 2013 release (which it probably won't, this being Blizzard) it will be Blizzard's first original title in more than fifteen years. Blizzard said years ago that their next MMO would be a new franchise not linked to any existing title, so Titan isn't a code word for Worlds of StarCraft or Diablo Online either.
The slate also confirms that Diablo III will have two expansions and that World of WarCraft will have two additional expansions, taking it up to its tenth anniversary. However, it does seem to be extremely optimistic over getting Sam Raimi's planned World of WarCraft movie out in 2013 when the project still seems to be in development hell.