It's no big mystery that the next generation of consoles from both Microsoft and Sony are headed their way into the hands of gamers this year, or in the early part of next year, at the latest. Blizzard is preparing for the onset of the next wave of hardware by opening eleven new positions dedicated to next-gen MMO development.
Based in the US, the openings were just posted on the company's jobs directory under the "Next-Gen MMO" header. Among the positions available, the company seeks to hire a franchise development producer to help lead the development of the game, a design department manager, a senior game producer, numerous software engineering positions, and a 3d environment art lead. The aforementioned art lead and an opening for a software engineer on engine/graphics appear to be listed as critical positions at the company.
Presumably, the "Next-Gen MMO" referred to is Project Titan—unless that's been scrapped, which is unlikely given how long it's been in development at Blizzard. Given that the absence of openings for most of the key design positions, it would be fair to assume that they've already been filled by existing staff at Blizzard.
Elsewhere on the site, Blizzard has an opening for a producer for its online service, Battle.net, whose key task will be to develop a "next-generation Battle.net desktop client." Thus far, the only way to connect to the service is through their games. A desktop app would allow Battle.net members to communicate with each other outside of games and potentially serve as a launcher for Blizzard's games and related websites.
All signs point to the development of a next-gen title, so it's only a matter of time Blizzard announces it in proper.