Capulous on 13 June 2013
From what I've gathered so far it seems like the following (right or wrong):
You can share all the games on your account with up to 10 people. These people have access to all games in your library. You can play any of your games at any time, but only one other person will be able to play any game in your library at a given time.
Basically, all your games are there for you to access, However, if anyone else wants to access a given game, they can only do that if none of the other people in your "family" is currently playing it. That means if you have 10 different games in your library, every one in your "family" can be playing a different game at the same time.
