Enabling Steam Family Sharing
When this question was asked, Steam Family Sharing was in beta. However, as of March 3rd 2014, Steam Family Sharing is out of beta and available to everyone.
If you open that tab now, you should see a screen like this:
When this question was asked, Steam Family Sharing was in beta. However, as of March 3rd 2014, Steam Family Sharing is out of beta and available to everyone.
If you open that tab now, you should see a screen like this: