Thread: What is custome variable in Google Analytics

In last recent days, Google Analytics gain a new look with new additional features.
In new forum you can found one more feature named 'Technology' also add. And also changed some hierarchy in the dashboard overview is mostly remain same, but add demographic also which tells about searcher area and language etc.
There also another option custom variable and user defined variable.
Can any one tell me about both these and for what purpose they are used in analytic.

Custom variables are name-value pair tags that you can insert in your tracking code in order to refine Google Analytics tracking. With custom variables, you can define additional segments to apply to your visitors other than the ones already provided by Analytics. This document describes custom variables and how you can set them up.