What are the green dots?

What are the green dots beneath number of posts on a persons name?

how does one give rep points? negative or positive?

Thnks

every time some 1 give's u an approval u get point's
and those green dot's tell u how many point's u have
if u click on that scale in the upper rite corner
you can say something about that thread or post
and either approve of it or not
click on the user cp at the top of every page
it will show u