Valve announced today that they are developing the beta for a new feature called Steam Family Sharing that will allow you to share your Steam library with close friends, just like you are lending them a physical game.

Though the full details are still unknown, the basic way the system appears to work is that up to 10 authorized friends can request to access your Steam account and download and play, through the cloud, most games you have available, and vice versa. To prevent abusing the system, if the user whose account you are borrowing from accesses their own account while you are using it, even if they are playing a different game than you are, you will be given a prompt that you have a few minutes to buy the game, or you will be kicked out.

Further details reveal that not every game will be available for sharing, though the specific games are unknown, and that purchased in-game items will not carry over to sharing, though it appears that DLC will. Also actions that can affect reputation in a game that are done by the player borrowing said game will carry over to the lender.

Though a few concerns and questions remain (Can a lender access his account when a game is installing to the borrower? If you’ve installed the game over the cloud and choose to buy it, does it have to be re-installed?) this is a tremendous idea that has been rumored for some time, but is still a welcome and exciting addition to Steam that provides a great opportunity to try out games that don’t usually have demos, as well as revive the borrowing concept, albeit in a slightly limited fashion.

Steam is accepting early beta applications now, while the release date for the full version is unknown.