A tag, a plastic bin, a metal chassis, and a six mile trek from the moment you check your bag at the counter until it gets on the plane. That's pretty much all there is too it. Well, of course there are a lot of scanners shooting off to match up your luggage tag to the number on the bin and chassis and there are a lot of machines working to x-ray your luggage and there are a lot of wheels spinning to zip your luggage around at crazy speeds in the right direction. So, hmm, I guess there's actually a lot to it.
Here's a detailed explanation on what's happening to your luggage inside the airport.