Sony have announced that the Beta for PlayStation now is coming to the PS4 on July 31st, meaning you can stream popular games right to your device. We don't know much about the specifics yet, but we do know that the service is later coming to PS3, PS Vita and some Sony televisions - allowing you to stream selected Sony games to all of those devices.
On top of this, a number of games can be played via the service at E3, including: Metal Gear Solid V: Ground Zeroes, Ultra Street Fighter 4, Dead Space 4 and God of War Ascension.
We still need to know more about the PlayStation Now library and how costing will be handled, but for now it looks like a great way to deal with a current lack of backwards compatibility.