If it is Blizzard's next MMO or franchise, the name alone is one of the most solid pieces of news that we've seen in years. The studio is notorious for its tight security and has let little slip about Titan or any of its other projects. Earlier this year, Blizzard confirmed that development on Titan was proceeding and that the company had shuffled around some of its staff to share between World of Warcraft and the upcoming "casual" MMO.
The name "Blackstone" is also somewhat similar to Blackthorne, an early Blizzard game from 1994.
While the website for Project Blackstone is currently defunct, rest assured we'll be keeping our eye on it to see what happens when or if Blizzard turns on the lights.