The Xbox One will allow games to be installed in segments, allowing you to play a game before the full game is downloaded. This is similar to features promised for the PlayStation 4. Background downloads for games will also be a feature as will background updates for games, which may do away with the update prompts you receive when starting up games on the Xbox 360.
Microsoft's "Smart Tech" matchmaking will attempt to eliminate waiting time for multiplayer games. It will also allow you to search for a multiplayer game while doing other activities such as watching TV. The new system will also more accurately track your skill levels that will let you find better matches based on skill, game style, and language.
Also similar to the PlayStation 4 share feature, the Xbox One will feature a Game DVR. This will let you capture gameplay and post your favorite highlights to your Live profile.
Microsoft also claims that games using the cloud will "evolve and learn from actual players, letting you play against your friends' shadow." It will allow for "dynamic, living worlds (that) evolve and improve the more you play." This feature was mentioned only in word.
Xbox Live Gold memberships will carry over to the Xbox One from the Xbox 360. Every gamer will have cloud storage access for profile and game data saves. Achievements will be improved and you will now be able to share your achievements with your friends. Speaking of friends, there will be a limit of 1,000 friends for Xbox Live on the Xbox One. There is no word on if this is a hard limit or not. Pricing was also not mentioned, but you should probably assume that Live will not suddenly become free once Xbox One is released.