PS4 games on PS3 console
There has been much debate about backwards compatibility regarding the PS4 (and Xbox One) during the build up to their respective launches. Can you play PS3 games on the PS4? If you've assumed that you will be able to then you're in for a shock.
Unfortunately, the answer, is no. That's the situation as it stands but Sony has said that in the future things will be different. See Xbox One vs PS4 games console comparison.
PS4 owners won't be able to use PS3 game discs in the new console, but they will be able to stream older titles.
Read: Should I buy a next-gen console: Is the PS4 and Xbox One worth it?
When will this happen?
Sony has confirmed that PlayStation Now will launch in the US this summer.
See also: What is PlayStation Now?
What PS3 games will I be able to play?
A list of titles hasn't been published yet. What we do know is that Sony is expecting to make a library of more than 3, 000 games available.
How will it work?
The streaming will be done in the cloud (over the internet) in a similar way to services like OnLive. Gamers will be able to rent individual titles or pay for a subscription for access to many games - details to be confirmed. The service will be initially available on PS4 with PS Vita and Bravia TVs to follow.