Many PlayStation 3 owners have shared access to their purchased games with friends through accessing each other's accounts. PlayStation 4 owners will be able to share games as well, but with slight differences, as detailed in Sony's new FAQ page on the subject.
Users can have two PS4 systems assigned to their account. One needs to be designated as the primary system to gain access to the PSN Store, PlayStation Plus and Remote Play. On the primary system, anyone can play purchased games and access PlayStation Plus benefits without needing a separate account.
You can download games registered to your account onto an unlimited number of PS4 consoles, however, you must be logged into the account that owns the game to start the game. You must also be logged in if you desire PlayStation Plus benefits. Only two PS4s can be logged into the same account concurrrently: the primary system and one other system.
Sony also warns that users should deactivate their PS4 as their primary system if you choose to "transfer or dispose of it", as the only way to deactivate a primary system is on the primary system itself. (Assumedly there is a way to have the primary system changed via customer service should this not be an option for you.)