The sharp eyes over at Wow.com noticed that Blizzard, on the 26 th of June, filed a trademark request with the USPT office “in the fields of computer games, paper-based products, and online entertainment services.”
While WoW shows up nowhere in the application, the domain wowcataclysm.com expired on June 26 th , and it is now “held by GoDaddy, who… handles Blizzard domains.” As such, the fansite is speculating that Cataclysm is likely yet another expansion to World of Warcraft. That being said, Blizzard is currently working on a ton of projects, most of which will never see the light of day, or which will be refined and transformed into something entirely different.
In fact, Cataclysm could just as likely be a “next generation MMO” or a pen and paper RPG based on the franchise. Regardless, assume Cataclysm is the biggest project presently in the works at Blizzard, whatever it might be.