I got my outter tie rods replaced last night, and got an alignment done this morning. The guy fixed a lot of things with the split (one side vs the other). Things were jacked up from the last moron that did my alignment. Anyways, I set things up and -0.5 camber each side, 1/32 toe-in, and caster was all the way at +5.2!!! We couldn't get the caster to come back to +4.
What does a lot of caster accomplish? The tech told me a lot of positive camber will cause the crown of the road to pull the car one way or another. True?

 

Caster is the angle drawn through the ball joints or SAI(steering Axis inclination). It helps the wheels come back to straight ahead after a turn(think shopping cart) and helps keep them there. Camber is the angle you see looking at the front wheels from the front of the car. Positive camber angle is tops closer and negative is tops farther away than bottom of wheel. 0 is Perpendicular to level ground. Yes too much camber angle can cause pull in crowned roads.

 

http://www.familycar.com/Alignment.htm great info in this link

 

Negative camber is when the tops of the tires are closer together. Positive is when the tops are out. Toe has MUCH, MUCH, MUCH more effect on the car pulling to one side than does camber.

Re OP: What does caster accomplish?

More caster can improve stability at speed. It also gains you negative camber when the wheel is turned. Both of these come at the expense of working the pump a bit harder.