The video game industry has known for a while that social networks represented a threat to the bottom line of traditional publishers – but the depth of that threat was unknown. A new survey of U.S. and U.K. players, though, underscores just how fast this new gaming category has grown – and gives new insight into who’s playing.

FarmVille

There are approximately 100 million people in America and the U.K. regularly playing social network games such as FarmVille and Mafia Wars, according to a study by Information Solutions Group and PopCap Games. That’s nowhere close to the number of people playing on the Nintendo Wii or Microsoft Xbox 360 – but for an industry that’s less than three years old, it’s impressive.