Blizzard have recently registered for a "computer game software" trademark in Benelux under the title of 'Eye of Azshara'. Since Azshara is a name from their WoW universe the chances are we're looking at the title for a new expansion in a game from that universe - but which one?
Azshara is both the name of an ancient elven queen and a region in World of Warcraft that hasn't been touched since the Cataclysm expansion years ago. The queen is responsible for using the Well of Eternity to summon the Burning Legion to Azeroth, before the Night Elves destroyed the well, splitting the continent into two and sinking the old Elven Capital. A large storm raged afterwards and it's possible that a game could be set within it, if Azshara refers to the character rather than the region. The region by the way is located North Eastern Kalimdor, at the site of the old Elven capital - just above Orgrimmar on WoW’s map - and was redesigned for Cataclysm with speculation being that the 'Eye' refers to a large island in Bilgewater Bay that resembles an eye from above.
Chances are if not the next expansion to WoW after Draenor that it is to be the title of the next Hearthstone expansion which Blizzard say will add 100 new cards to the game. After all, there's recently been a new card back added to the game and robot blueprints mailed out to Hearthstone community members, and the island in Bilgewater is help by goblins who often experiment with mechanical things.
Blizzcon 2014 will be soon though, so hopefully details will emerge there on just what Eye of Azshara is to be.