The game is described on Goblinworks' website as:
a hybrid sandbox/theme park-style MMO roleplaying game where characters explore, develop, and dominate the River Kingdoms, a treacherous no-man's-land of squabbling kingdoms on the edge of wilderness.
I'm no expert on MMOs, but the sandbox/theme park hybrid does seem pretty par for the course. Given some of the other information on the Goblinworks page about the game, I wonder just how much of Pathfinder will actually make it into the game, other than the name (emphasis added):
Players explore, adventure, develop, and dominate their domains by playing fighters, rogues, wizards, or any of Pathfinder's many character types, or they can use the game's archetype system go beyond the standard options to create nearly any sort of character imaginable.
In any event, congratulations to Paizo, and it will be interesting to see how Pathfinder fans react to the news and the game itself, once it goes live.