Microsoft is acquiring Massive, a company that does in-game advertising. Massive sells a lot of those billboards, vending machines and other types of ads you see in games more and more these days. Cnet’s Daniel Terdiman says:
But by buying Massive, Microsoft is putting itself in a position to cash in both from the sale of games, and from the revenue generated by the inserted ads. This will also allow Microsoft to maintain more control over how the ads are placed and to consider new business models in which it could potentially allow the ads to subsidize lower prices on its game titles.
Joystiq pretty much says the same thing, that Microsoft is creating multiple revenue streams. They have a list of seventeen (17!) revenue streams the Xbox 360 already has, everything from music video distribution to Xbox Live sponsored weekends.