Another rumor which states that Blizzard's next expansion pack will be called "Emerald Nightmare".

This rumor originated on MMO-Champion.com:

Leak Confirms 'Emerald Nightmare' as Next World of Warcraft Expansion

While it will not surprise players familiar with the game's extensive lore, an anonymous source within the Activision-Blizzard team responsible for the best-selling World of Warcraft MMORPG and it's two expansions has confirmed the next to be titled 'Emerald Nightmare'. It will take places after the events of "Stormrage", a novel authored by Richard A. Knaak which explores Malfurion Stormrage's attempts to cleanse the Emerald Dream of Xavius's corruption. The source also confirmed a tentative release date of Q4 2012, consistent with the release schedule of previous expansions.

It sounds a little dubious since it's written "news style" to give the appearance that it was copied from another source, however it did in fact originate on MMO-Champion.

It was re-posted on the official Blizzard forums, however it was only up for 1 hour before Blizzard deleted the thread. You can see the original read here.

Cached copies of the Forum Post (http://us.battle.net/wow/en/forum/topic/2016644135) can be found here and here, but they won't be up for much longer though.

The user Leynah wrote: "Just got word from my anonymous source at Blizzard that this source smells and leaves crumbs all over his desk. He made no mention of refuting the claim... just complained about the guy."

As you recall, Cataclysm details were "leaked" on MMO-Champion, however that was by Boubouille (the site admin) who had a known relationship with Blizzard. This 'Emerald Nightmare' rumor was started by a new user.

It's not really a big surprise, though, if the next expansion has something to do with the Emerald Dream. Blizzard has already hinted at it in the past (future expansions packs will be "a dream and a nightmare") and it has been speculated by many users.

A future expansion pack will no doubt contain the Emerald Dream and Nightmare, but the origin of this rumor is questionable (e.g. "It will take places", "World of Warcraft MMORPG and it's two expansions" (pre-Cataclysm rumor I'm guessing), the "news-look" even though this is the original source, the age of the account, and that it was re-posted to the WoW forums seconds later by a Level 1 account named 'Fdhgj', who also then deleted their own account.) So yeah.. I'm calling bullshit on this rumor.