Just very recently, we confirmed that the PS4 won’t have any used game restrictions or a required daily online check-in to use the console offline. With this said, in order to access online play on the PS4, you will be needing a Playstation Plus membership, as revealed quite recently. The approach here is similar to how XBOX Live memberships work, so though it may be new to Playstation users, it’s not that new to XBOX 360 users. In either case, your PS3 Playstation Plus account is transferable to the PS4, and it seems like you’ll still get all of the perks that are currently being held right now!
E3 2013: Playstation Plus Membership Required for PS4 Online Play