Steam Family Sharing will allow users to share Steam libraries on shared computers. Basically, people no longer have to buy separate copies of the same game if they live under the same roof.
The catch is that only one user can access a particular library at a time, and that games that feature additional DRM, such as Games For Windows Live or UPlay will not work with the new feature. Beta testing for Family Sharing starts later this month. You can read more HERE.
Does anyone else think Family Sharing is an awful name? Every time I hear it, I get this creepy image of some corporate yuppie breeding program.