It is an underused feature of the forums. I always use it to add points to the posters that include good pics of Qview and for those that make good points or go out of the way to look stuff up for others.
I beleive the reputation is displayed under the user's info on right side top of post as green bars. We all start off with one. As reputation increases, so does the bar.
I just gave you points for asking a GODD question.
If anyone else has wondered how to give points to a poster, click on the justice scales on top right corner of post and the rest is self explanatory.