Once upon a time, Gaikai was a tiny, optimistic company throwing everything at the wall, desperate to find a use for its cloud gaming technology. Today, those dreams have been fulfilled: Gaikai founder David Perry walked out on stage at Sony's PlayStation 4 event, confirming that the new PlayStation will use that tech to stream games over the internet.

Previously, we'd heard that Gaikai would just be used to deliver legacy PlayStation 3 titles on the new platform, but that's not the case quite yet. Instead, it sounds like Gaikai will maintain its original business model of allowing you to try what amounts to a demo of a game — any game — for free before you purchase a disc or new play-as-you-download title. Perry suggests that you'll be able to "instantly experience" any title you see in the PlayStation Store.

What's more, Sony says you'll be able to stream PlayStation 4 games to a PlayStation Vita handheld with new Remote Play functionality, using the PlayStation 4 like a server. Nvidia's Project Shield is trying a similar tactic.

But can you buy streaming PS4 games?

Perry also says the service is now partnered with Facebook and Ustream, and will allow you to spectate any friend playing a game in real time, and you'll be able to post comments that players can see... a popular feature of Gaikai's former rival OnLive. Now, though, you'll be able to choose when you want to be spectated, pressing the Share button on the controller to broadcast your gameplay live. You'll even take virtually take over a friend's controller if they have to run out the door, says Perry.

And that's not all Gaikai is bringing to the PlayStation ecosystem, Perry tells the crowd: The Gaikai founder said that he expects the streaming technology to be able to deliver legacy titles from previous PlayStation platforms (including PS1, PS2, and PS3) to any device, anywhere, in the future. Unfortunately, that future is not now: PlayStation 3 titles won't be natively playable on the PlayStation 4, and it sounds like a streaming solution for that backwards compatibility is also some ways out.