If you mean the green dots under senior/junior member, those have to do with reputation, not post numbers.
Going from Junior Member to Senior Member has to do with reaching, i think 150 posts. Might not the exact number.
Green dots are about reputation. Though, before asking, the reputation system is not at all understood, even by mods. haha.
The other green light, next to your name is an online/offline indicator. I think pickles confused her green lights ( ;
Also we have a User2User Tech section for these questions. Might post them there rather than Prayer Request.