I know there will be some comparison between the recent Steam Family Sharing announcement and what Microsoft proposed, to a flock of airborne tomatoes I might add, for the Xbox One. Steam integrates some level of copy discouragement by accounts which identify a catalog of content with an individual. This account, user name and password, tends to be more precious to the licensee than a physical disk or a nondescript blob of bits.
The point is not to prevent unauthorized copying, however; the point is to increase sales.
Account information is used, not just for authentication, but to add value to the service. If you log in to your account from a friend's computer, you have access to your content and it can be installed to their machine. This is slightly more convenient, given a fast internet connection, than carrying a DRM-free game on physical storage (unless, of course, paid licenses are revoked or something). Soon, authorized friends will also be able to borrow your library when you are not using it if their devices are authorized by your account.
Microsoft has a similar authentication system through Xbox Live. The Xbox One also proposed a sharing feature with the caveat that all devices would need a small, few kilobyte, internet connection once every 24 hours.
The general public went mental.
The debate (debacle?) between online sharing and online restrictions saw fans of the idea point to the PC platform and how Steam has similar restrictions. Sure, Steam has an offline mode, but it is otherwise just as restrictive; Valve gets away with it, Microsoft should too!
It is true, Microsoft has a more difficult time with public relations than Valve does with Steam. However, like EA and their troubles with Origin, they have shown themselves to be less reliable than Valve over time. When a purchase is made on Steam, it has been kept available to the best of their abilities. Microsoft, on the other hand, bricked the multiplayer and online features of each and every original Xbox title. Microsoft did a terrible job explaining how the policy benefits customers, and that is declared reason for the backlash, but had they acquired trust from their customers over the years then this might have just blown over. Even still, I find Steam Family Sharing to be a completely different situation from what we just experienced in the console space.
So then, apart from banked good faith, what is the actual difference?
Steam is not the only place to get PC games!
Games could be purchased at retail or competing online services such as GoG.com. Customers who disagree with the Xbox One license have nowhere else to go. In the event that a game is available only with restrictive DRM, which many are, the publisher and/or developer holds responsibility. There is little stopping a game from being released, like The Witcher 3, DRM-free at launch and trusting the user to be ethical with their bits.
Unfortunately for Xbox Division, controlling the point of sale is how they expect to recover the subsidized hardware. Their certification and retail policies cannot be circumvented because that is their business model: lose some money acquiring customers who then have no choice but to give you money in return.
This is not the case on Windows, Mac, and Linux. It is easy to confuse Steam with "PC Gaming", however, due to how common it is. They were early, they were compelling, but most of all they were consistent. Their trust was earned and, moreover, is not even required to enjoy the PC platform.