You are correct, sir. (and thank you for the kind words upstream, much appreciated)possibly the green squares come in blocks of 100 for each square.
As soon as a person gets to 100 rep points, a second square shows up. Plus, the number of points you give out each time is increased by 1. So, the squares actually tell you how many points you would get from that person were they so inclined as to bestow them upon one of your posts.
Name changes (spectacular aura, shiny shiny jewel) occur as you reach other totals.... 50, 75, 125 and so on.