Is the PS4 compatible with PS3 games?

Will the PS4 play PS3 games? 

At the Sony PlayStation 4 conderence, Dave Perry said PS3 games are "not natively supported."

This does not necessarily mean the extensive collection of PlayStation games won't be available to users as it would appear gamers will be able to use the console’s cloud service to access to a wide array of past PlayStation.

So basically that seems to mean you won’t be able to use your PS3 game disks in the PS4 and you might just have to pay again for your favourite game if you want to use it on the PS4.