Let me know if there are any more unique pictures. This thread is for us as a community to make our best guess at how all of this fits together. I'll edit the OP as we work it out.

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1. PSN profile

2. Recent Activity/News Feed

3. Spectating a straming game

4. No Back option listed makes me suspect this is the surface level of the UI.

5. While in a game pressing the Share button brings this sub menu up.

The first picture. What I assume is a gamer's (PSN) profile. Set up like facebook, profile picture, recent activity, etc. But it concentrates on what you use a PS4 for. Games. So trophies front and center, but more importantly notice he is playing Knack, that video is a live stream of what he is playing. So it is my understanding you will be able to browse through you friends, and potential friends, to see they playing their game. You can join them, send messages, view their pictures and videos, just watch them play, or video/voice chat even at the same time.

Ugh. I don't care. I want quick access to my games and the PS Store. I don't actually care what my friends are doing. I don't want the Windows 8 start screen. I hope these are layers further into the UI. I'll rage if I have to claw through a Facebook clone just to play.

Still, perhaps it won't be like that, and the social stuff will be to the side. They did talk about not having a delay between wanting to play a game and actually playing it.

As these picture might just be its own thing actually. Look at the second picture. It is all social stuff. I think this is a serpate app or portion of the actual UI. It is just a news feed. Sony hasn't shown us the acutally OS or UI.

It's like Windows 8 and the new PS Store had an ugly baby.

The second image is really out of place and was even separate in the conference. It's just a screen similar to "What's New" on PS3. Agree?

No. Looks more like an activity feed.

1. Profile of a friend
2. Not sure, some social feed thing
3. The game stream screen
4. Surface level of the store maybe? (store icon in corner, and it's a list of games) Could be more of a hybrid of store and game list.
5. Agree, looks like share function

Seems quite unfinished though, so I wouldn't read too much into it. I mean for 2 how can you join or command without having bought the game?

They specifically stated you don't need the game due to the power of Gaikai.

Wait, how does this work? I mean, I get that it's possible, but how much do they let you do with a game without buying it? I would think that if you are commanding (this is the taking over option right?) then you are essentially playing the game.