Some info from us PSN Blog about game sharing and friends lists
http://us.playstation.com/ps4/features/ps4-faq/
Sharing games you purchase from PlayStation®Store
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.
Sharing benefits from PlayStation®Plus
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.
Playing games you purchase from PlayStation®Store
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. * Only you can start games that you download.
Enjoying benefits from PlayStation®Plus
If you join PlayStation®Plus, you can sign in to PSN℠ from any PS4™ system and enjoy your membership benefits.
Playing on other PS4™ systems when you are not at home
* You can use up to 2 systems concurrently: the system activated as your "primary" PS4™ system, and one other system
Coinciding with the release of the PS4™ system, you will be able to become Friends with up to 2,000 people on PSN℠. You can view your Friends on any device you have signed in to with your PSN℠ account. The number of players displayed varies for each device.
PS4™ systemPS4™ system
All of your Friends can be displayed.
PS3™ systemPS3™ system
A maximum of 100 players can be displayed.
PS Vita systemPS Vita system
All of your Friends can be displayed in Friends(Friends). Support for the ability to display all of your Friends in most applications and games is planned. (However, some titles will be limited to the current 100 Friends.) *1
Smartphone or other device with PlayStation®App installed.Smartphone or other device with PlayStation®App installed.
All of your Friends can be displayed.
*1 For details on which 100 players are displayed, see below.
Which 100 players are displayed?
1. If you have sent or received Friend requests that haven't been approved yet, up to 10 of the most recent recipients and 10 of the most recent senders are displayed.
2. Your Friends are displayed.
If the sum of players from point (1) and your currently online Friends is more than 100, your currently online Friends are displayed by online ID in alphabetical order until the limit of 100 players is reached.
If the sum of players from point (1) and your currently online Friends is less than 100, your currently offline Friends are also displayed by online ID in alphabetical order until the limit of 100 players is reached.
3. If the sum of players from point (1) and all of your Friends from point (2) is less than 100, any remaining recipients of your Friend requests are displayed, followed by any remaining players who sent Friend requests to you, until the limit of 100 players is reached.
You must sign out of PSN℠ and then sign in again to update the players who are displayed. When doing this, also sign out of all other devices that you are signed in to PSN℠ on.