Sony has clarified how used and digital games will on the PS4 with some new FAQs, confirming the need to activate your “primary” PS4 console to enjoy certain benefits. The FAQs state that the “primary” PS4 console will allow all users of the system to enjoy downloaded games, but games on other systems can only be used by the PSN account that purchased them.
On the primary console, games you download can be played by users who share your PS4 system, such as your family and friends. You do not have to log in to the system for other users to play these games. If you join PlayStation Plus, benefits such as online multiplayer features that come with that membership can be enjoyed by users who share your PS4 system. You do not have to log in to the system for other users to enjoy these benefits.
However, on a secondary console , games you purchase can be downloaded and played on any PS4 system if you sign in to PSN. There is no limit on the number of systems you can use, but only you can start games that you download. In addition, you can use up to 2 systems concurrently: the system activated as your “primary” PS4 system, and one other system.
You can share disc games with your friends and play used disc games on your PS4 system just like you can on a PlayStation 3 system. You do not have to connect to the Internet or pay any usage fees to play used games.