Slightly OT, but it reminds me of the similar (but not identical) Canadian English phrase:
That's cool, eh?
It's a sentence softener... and a way to get general acceptance from the person you are speaking with.
Anyway, best described with an example:
girl 1: That's girl's outfit is SO ugly!
girl 2: OMG, how does she even live with herself?
girl 1: I know, right? She is SOooo uncool.
"I know" can be a strong statement, so adding the question "right?" is a way of getting general acceptance from the other person.