Speaking at Develop, Neil Brown, Sony’s R&D senior team leader, outlined the process that lets you access your games on other machines at other people’s houses:

“You can visit your friends house you can log into your account and play any game from your digital library, which is good. But how useful is that if it takes half a day to download the game you want to play? With Play As You Download you get much quicker access to at least the first section of the game so you can start playing quicker. So this makes a digital library a practical option in the real world.”

“A similar system also works on Blu-ray, chunks are automatically copied to the hard drive in the background. This means that after the first few minutes your game can rely on having faster read speeds from the hard drive. Which provides a better experience for players, and this is a completely background process for the player. They don’t have to wait for anything to install before playing the game. The game will launch as soon as the disk has been put in the drive.” 

http://www.officialplaystationmagazine.co.uk/2013/07/10/ps4s-digital-library-lets-you-play-your-games-anywhere-on-anyones-console/

So what the Xbox 360 has had for years....

Well good news is better than no news. And i guess the main feature here is the instant play function where you can play the game as you're downloading. 

only if you are always online...

Its the little features Live has over PSN that differentiated them. But the average 360 gamer (including me), didn't know things like this to use it as a talking point. lol damn

Now that Sony caught up, the windows closed :(

this is just like the PS3 currently except for the ability to start playing while downloading. I wonder if they will have a limit to the number of consoles your ID can be on.

PS3 has had this too, but the difference here is that you can play as you download.

I'm really curious as to how well instant play as you're downloading will work. Are there games that allow this already or is this new tech? Also it's a bout time ps3 got the install disk feature- I'm ready for shorter loading times (Mass Effect 2 on ps3 could've really used this feature).

good, im glad they improved that. with no 24 hour check in, a damn hurricane is about to pop in and fuck up the weekend, so i doubt i will have electricity for a day or more and internet, who knows. at least i can play offline though.

oh well, i got the coolers ready for ice and beer. :)

PS3 have it limited to two consoles... you need to manually deactivate the one console to play in another (and that can be make only in six months intervals).

Seems a evolution of the PS3 system... we need more info to know how that works.

Do you mean the playing your digital games on your friends PS3 part? Because you could always do that. What is new here is that you can play as you download. You can also choose to download the single player or the multiplayer first so you can do what you want as quickly as possible.