Having gone live yesterday, Chapter 1 is receiving mixed feelings from fans. While I'm not able to play it (I'm too much of a lowly scrub to be able to), I still think some new lore based quests sounds like a lot of fun. Here's the trailer, plus the details if you're level 110. 

Who: Level 110 players
Where: Begins in Stormwind for Alliance and Undercity for Horde
Rewards: Gold, Reputation, New Items from limited time World Quests, Faction Pride

This chapter is a part of a limited time event leading up to the launch of Battle for Azeroth.