Microsoft has released some details on the "XBox 2", most of which seem to imply a stronger focus on online play and a some sort of formation of a community. For one, each player will have their own profile called an "Gamer Card" which will store, among other things, skill rankings for every game played, interests and lifestyle information and so on. Presumably this will be (optionally) made publicly viewable via XBox live, as opposed to just letting your brother know that you happen to be good at DDR Ultramix. Also very probably, this is also where all the player-specific game data (save games, highscores, options, etc.) will be stored as well.

Microsoft also plans to develop some sort of electronic online marketplace. The intended usage is for users to make custom levels, maps, or other game content, and then sell them online on the marketplace for credits. What do you do with the credits you've earned? Why, buy other people's custom levels, maps and and other game content of course!

The other details are less "revolutionary" and more technical minded. The processor will be multicore, with multiple simulatenous user capabilities emphasized (the example given is one user can play a game while another user can watch DVDs, though how that might work without dual TV outputs, I'm not sure). The XBox 2 will support high definition audio out of the box, and Microsoft will try to encourage more developers to take advantage of surround sounds for their games with the XNA SDK.

Update: according to a CNN article, the marketplace will actually allow you to sell your online content and such for real world money. Furthermore, among the example usage given is a player being able to buy a slightly faster car. If these "slightly faster cars" are available for online multiplayer play, unless the benefits gained by these cars are capped, the "richest kid" will tend to always win, having an advantage over all other players. The article mentions that "this is something of a departure for game developers. While there has been a thriving market for in-game items for some time on eBay and other auction sites, game companies have typically frowned on the practice." Preventing the richest kid from always winning is one of the reasons for not allowing people to simply buy their way up the game.