Sony has released a FAQ on their website and one of them explains their digital sharing.
PS4 Digital Sharing
Registering your PS4 as your primary system will allow other users who play on the same console with different accounts access to any games you’ve downloaded without you having to log in. Additionally, if you have PS Plus and register a PS4 as your primary console, then every account that plays on that system will be able to make use of certain benefits like online multiplayer even without their own PS Plus subscription.
If you want to play on another PS4 that isn’t your primary console, you can download any game you’ve bought on the PS Store as long as you sign into PSN. Only you’ll be able to start the games you’ve downloaded, and you can only be logged into two consoles at any one time: your primary PS4 and one other secondary one (like a friend’s). The good news is there’s no limit on the number of systems you can download your games to. You have to be logged in in order to play, but from the sounds of things this means you can share digital games with as many mates as you like, though only one of these secondary consoles will be able to play a title at any given time and you’ll have to tell them your password so they can log in.
Video Game Sanctum 