The Playstation 4 is a great system, however it does have a couple of things to be desired and the big one is the ability to play past consoles games namely Playstation and Playstation 2. A short while ago it was rumored that maybe Sony could have been considering emulation for the consoles on the system but now Sony has officially confirmed they are bringing some kind of backwards compatibility for the Playstation 2 to the Playstation 4, as quoted by Wired:
We are working on utilizing PS2 emulation technology to bring PS2 games forward to the current generation,”
Unfortunately no other details have been shared and we will have to wait and see what exactly Sony plans to do. While I would like a similar idea to the Xbox One and be able to put my discs in for a file on the console I do find this unlikely, but this is Sony we have to be patient and see what they have in store for us.