Players can receive these gifts in their mail box if they log in during the anniversary:

Celebration Package - Increases experience and reputation gains from kills by 11% for 1 hour. (10 second cooldown) Gnoll Celebration Wand - Puts a gnoll costume on a targeted party member (5 charges) Murloc Celebration Wand - Puts a murloc (Mmmmrrrrrrghhhh) costume on a targeted party member (5 charges) Exquisite Costume Set: Edwin VanCleef - Allows players to dress up as Edwin VanCleef, the boss of the Deadmines (50 charges) Inflatable Thunderfury, Blessed Blade of the Windseeker - Allows players to equip an inflatable version of the popular weapon and unlocks the achievement  “Did someone say. . . ?” across the whole account

Players can also receive the “WoW’s 11th Anniversary Achievement” by logging in before November 30th. Blizzard also launched a hashtag, #11YearsOfWow, in honor of the momentous event. 

The game is expecting its newest expansion, World of Warcraft: Legion on or before September 21, 2016, adding a new playable hero class to the game, the Demon Hunter.

What to expect from WoW s 11th Anniversary   World of Warcraft - 84