Valve has announced a Family Sharing service for Steam that lets gamers share their library of games on 10 additional devices. The caveat here is that a game in the shared library can only be accessible to one account at a time.
The Family Sharing service will enter beta sometime next week, wherein a 1,000 users will be initially granted access to try out the service. If you are interested, you can head over to the Family Sharing community on Steam and register for the beta. Steam does note that not all games can be shared. Games that need third party serial keys and those that need users to subscribe on a recurring basis will not be eligible for this service. Games that are region locked will not be usable outside the region.
Game content like DLCs and unlocked features will also be accessible to the borrower. Game accounts or save files cannot be shared, which means that each account that has access to a shared games library will be discrete and feature its own game saves and achievements.
Also, if you’re the owner, you will not have any restrictions when it comes to accessing your game library. If one of your borrowers is accessing a game and you do the same, the borrower will have a few minutes to quit the game or buy it outright.