'Loose' driveshaft?

Hey all:

I was hanging out under my 2008 taco yesterday and noticed the driveshaft is sitting in this housing, and the driveshaft doesn't seem to be attached to anything at that point, it just sits in this housing and is free to move up and down a few inches.

So, the big question I need answered is........is this normal??? My first thought was bravo to toyota for designing a driveshaft housing that allows it to flex and move, but I need to make sure this is normal so I dont have problems down the road. I have attached a photo so you can see what area of the driveshaft im talking about.

 

that's the center support bearing. Some call it the carrier bearing, But that always makes me think of a 4 wheeler axle. It will have a little bit of play, but how much is kinda argued. Some say a quarter inch, some say an inch. Mine moves a good bit too.. But I don't know how much its supposed to either

 

It's shouldn't move more then a 1/4" anymore than that it needs to be replaced before you start throwing u joints