will steam be there for ps4 ?

Maybe if Valve decides to put cross-platform play again.

Don't think so.

No, not with the Steam-box coming out.

No, if your are talking about the digital distribution service, but as we haven't seen PS4 yet, I would say we can't completely deny the possibility that it is powered by the actual steam engine. That would be badass.

No, because Sony has the PSN store. Why would they willingly give their profits to Valve when they don't have to?

Wait, did anyone even use it for PS3?

Never heard anything about Steam for PS3, I just knew of its existence.

Short answer,No.

(buy things can change in a couple of years)

No, as the Software brings most money to the consoles. Steam would totally screw that.

Steam is making their own console anyways. check it out, it's called Steambox.