According Eurogamer, Ubisoft's service of additional and social content, Uplay, will be available in for PS4 and Xbox One. Uplay will be available on all next-gen Ubisoft titles, including Assassin's Creed 4: Black Flag, The Crew, The Division, Watch Dogs, Child of Light, Valiant Hearts and Trials Fusion.
Although it wasn't revealed how Uplay will work, it will most likely be similar to how it works in the curren gen, where many Ubisoft games include an Uplay application on the main menu. When this option is selected, it takes you out of the game and displays a feed of social events and showing what you and your friends have done in-game, as well as earn Uplay points for completing set achivements. These Uplay points can then be used to unlock small pieces of DLC (weapons, costumes).
Ubisoft also confirmed that players will be able to use the service on the PS4 and Xbox One in November, on their respective launch date. In addition, the PC Uplay will be updated to Version 4.0 in October, and will add a social wall and download manager.
The Xbox One is scheduled to release on the 22nd of November in 13 countries, arriving at the rest of the world in 2014. The PS4 will be released on the 15th of November in North America, arriving at Europe two weeks later, on the 29th of November.