An anonymous reader writes: We've frequently discussed the growing trend among video game publishers to adopt a business model in which downloading and playing the game is free, but part of the gameplay is supported by microtransactions. There have been a number of success stories, such as Dungeons & Dragons Online and Lord of the Rings Online. During a talk at the Game Developers Conference this week, Valve's Joe Ludwig officially added Team Fortress 2 to that list, revealing that the game has seen a 12-fold increase in revenue since the switch. He said, 'The trouble is, when you're a AAA box game, the only people who can earn you new revenue are the people who haven't bought your game. This drives you to build new content to attract new people. There's a fundamental tension between building the game to satisfy existing players and attract new players.' He also explained how they tried to do right by their existing playerbase: 'We dealt with the pay-to-win concern in a few ways. The first was to make items involve tradeoffs, so there's no clear winner between two items. But by far the biggest thing we did to change this perception was to make all the items that change the game free. You can get them from item drops, or from the crafting system. It might be a little easier to buy them in the store, but you can get them without paying.'