Identifying giver or Reputation?

[BADAZGTP]

How come some have the green dots beside them and some don't?

[TDCRacing]

same with mine. Some are green and some are gray.

[Zef_66]

same with mine. Some are green and some are gray.

I believe that green dots mean ones that you got Positive rep from. grey ones are rep that is neutral. If someone comes on here, and doesn't have any rep, he/she can't give any rep. They can leave a comment, but it doesn't affect your reputation positive or negative.