PS3 and PS4 Crossplay?

When I am in mutliplayer in a game that is on both systems, can I use my PS4 to play with people who have a PS3?

@Mighty-Lu-Bu:

No

Interesting. So besides Final Fantasy a realm reborn where there is crossplay, PS4 has different online servers than PS3 for the same games?

Yes.

Yes exactly, look at GTA 5 as an example.