"Jason Ainsworth plays the online game Second Life at least four hours a day. In the game, he runs a virtual real estate development business. But his after-tax profit - about $1,800 a month - is real, and it's enough to pay the mortgage on his home in Las Vegas. For many people, what are known as massively multiplayer online games have become significant sources of income....So earning potential is starting to become one of the variables for determining attractiveness of game-play. I wonder how long before it's a standard part of game reviews, along with graphics, controls, action, story line, etc.?"