Age of Empires Online will close on July 1, 2014. On that day, the service will cease to function, and no further games can be played. The servers will be taken offline, and no features of the game or the game service will work without the servers. Until that date, the game will continue to fully function just as it does now. You can quest, raid, chat and trade as much as you like until then.
However, no one new can join the game. If you have ever downloaded the game, from Games for Windows Live, Steam or other digital sources, or if you bought a code at a retail store, you can still play the game in its entirety. New players cannot join.