Karma is a way to say thank you to a poster that was of particular good help to you on your posted question or problem. It's optional and a simple written thank you response in your posting is probably just as effective a feedback as the karma click is. Karma was just reintroduced a month or so ago, after being attempted a year or more ago with lots of drama and emotional comments, as that prior version carried both positive and negative karma counts, so lots of fun all around for many.

Lefty