You only receive rep points when someone gives you a rep comment. For example, if I repped you, you'd receive 71 rep points because I have 71 powers. For every 100 rep points you get, you receive a green bar and a power. You also receive a green bar and a power for every so many posts you make. Mine started out at 100 and doubled on up through, and now it's 1000 posts. I no longer receive green bars because I have them all.
I do still receive a power, however, for every 1000 posts I make..