Jack Trenton revealed at E3 that the Playstation 4 won't put any restrictions on second-hand games. During the presentation it was revealed that we'll be able to trade in games at retail, sell them to other people, lend them to friends, or keep them forever.
It won't require any online connectivity to operate. You won't need to register the machine at any time during the day in order to play. Basically Sony just announced that they're not doing anything that has caused Microsoft so many problems since they announced Xbox One last month.
As a nice little footnote, PS Plus will also cover all consoles, including PS3, PS4 and PS Vita.