Microsoft quietly updated its Games for Windows Live service to version 3.0 today. The biggest new feature, according to the company, is how users can now access the marketplace to buy content while playing any supported title and have it download and install in the background. The feature should help streamline digital distribution on PCs and follows a growing trend of generating additional revenue through post-release game content – Valve offers a similar feature on Steam and even Apple is supporting it for iPhone apps.

In-game account management is also now possible, so you won't have to stop playing Fallout 3 (or whatever) in order to buy some Microsoft Points, edit your credit card info, or redeem codes. While most gamers will agree the aforementioned features are welcome additions to Games for Windows, there’s also a couple more that are meant to appease publishers.

This includes two new anti-piracy solutions: a Server Side Authentication method that links the game license to a user’s Gamertag, allowing you to game from anywhere but apparently also making used game discs worthless for sale or giving away; and Zero Day Piracy Protection to keep games from launching before the street date the publisher has set for the game. The update is available as a free download here.