Effort in the job effort!

I finally got around to setting up a Monster account. I've had my profile sitting idle 'cause I have a few questions on writing it:

- On the Work Experience section, what's the difference between the summary and description?
- What should I put as my summary in the Education section?
- What is retention in the context of "Customer service and retention"?

That's all I can think of at the moment...any feedback would be greatly appreciated!!!