I have my first two Followers: Qiana Moonshadow who apparently is an expert at fighting/doing quests in forest areas and a rogue whose name I apparently didn't write down nor her specialties.
My take on the Followers now is that they are a mini-game sort of like Battle Pets. Missions become available and you look at the quest and what is being fought, look at your available Followers and choose the one who you think can complete the quest. You do get some indication going in on your likely success rate with that Follower.
Bozoid that I am I just willy nilly sent them both off and one Succeeded and one Failed. I suppose if a quest comes up that neither of your current followers have a good chance of completing you should just not send anyone, but as long as there's better than half chance, off they go.
So far the Quests take the Followers 30 minutes to complete, then you have a message that they are complete and you should return to your garrison. All interaction with them is through the command table where you get the missions. They aren't lounging about your garrison having a smoke between quests.
I'll try to be more strategic about who I send where henceforth. And my collecting instincts are now in gear so I want to catch them all and have a better variety of possible minions for quests which may come up.
The Follower Interface: