Basically mean Okay. I get it. STFU.
Also, used as "whatever" at teachers or boring conversations.
Math teacher: Anyone got it?
Kid: Sure, sure. *Got back to desk, Listens to iPod, forgetting the work*
Girlfriend: ZOMG! Did you just saw him with her? I cannot believe his with her already just right after our broke up! Blablablblablblaaa
Me: Sure, sure.
Girlfriend: Are. You. Even. Listening.
Boy: I love you.
Girl: Sure, sure.