
(again)
Cathy_C's thread at the top of the Newbie forum,
Next on our tour, if you'll look to the left, you'll notice... explains about the rep points (as well as a few other things), and where they are located and how to find the hidden 'reputation level'.
Basically members give reputation points by clicking on a scale on the bottom left of posts. When you click the scales a box will appear that allows you to approve (or disapprove-but I think this may have been disabled now for members) of a poster's comments, and it alllows you to add a comment if you choose (which you don't, you can leave it blank. But where's the fun in that. You could just leave a --

).
You add to someone's rep points if you feel the person is helpful, trustworthy, supportive, funny, made a useful comment, you agreed with something that was said, etc.
Everyone starts out with a reputation score of 10. To become a Super Member, you just need to keep that score of 10 and accumulate 50 posts (at which point I believe you get a slightly larger mail box and are allowed to upload a custom avatar--however, don't quote me on that, I'd have to check).
Mostly giving rep points can be used for a bit of fun and for short messages to members instead of using the private message function.
This sticky in the Newbie forum is very helpful, it explains a lot, including where the hidden reps are located. For the reputation levels see
this thread. There are other threads around on rep points. If you search for Rep Points, put the Rep Points in between " " and it should help with the search a bit e.g. "Rep Points"