So what was Titan? For starters, according to three people I spoke with, it would have taken place on a near-future version of Earth, in a science-fiction depiction of the world where mankind has successfully fought off an alien invasion. Players would join one of three factions waging a cold war over control of the planet, and zones planned for the game ranged from the west coast of the United States to Europe, South America, and Australia, according to a source. Blizzard's plan was to make the game world huge, and to keep adding areas with expansions in the years after launch.
The main concept was this: you, the player, would maintain a mundane job—butchering, engineering, entrepreneurship—during the day, while waging clandestine warfare against opposing factions at night (or between work hours).
One potential scenario, described to me by a person who saw the game, might have gone something like this: You're working for a corporation, helping run a shop, when you're called for a mission by your faction, so you run into an elevator, switch outfits superhero-style, and go off to fight enemies with a group of friends or allies. Or you can just ignore the combat and keep doing your job, which could mean anything from tinkering with vehicles as a mechanic to running your own business as an entrepreneur.