In this post, part one of a four series, we get the basics for how Garrisons will work -- how your Garrison is part of the leveling process, how followers will work and how you can recruit them, the missions you can send them on and how that will benefit the Garrison, how we'll expand the Garrison with new building and use each zone to expand their role in the expansion.
This in particular is of interest - you apparently won't just have the one Garrison, but a linked series of fortifications throughout Draenor to serve as your means of recruiting and defending your followers for the push against the Iron Horde.As the story unfolds, you'll find that Garrisons are intimately integrated into every zone-whether you choose to follow the main quest path or just head off into the hills to explore, you will meet allies (and enemies) in every corner of the world. While your main fortress will always be in Shadowmoon Valley (Alliance) or Frostfire Ridge (Horde), you will establish Garrison outposts in Gorgrond, Talador, Nagrand, and Spires of Arak, all customized based on your building choices. Eventually, your forces will span the continent, and you will have an army capable of assaulting the fortified Iron Horde Foundry. Will your troops succeed? That's entirely up to you, commander.
Head over to the official site for more details.