Girls, What does it mean if a girl laughs and says "shut up!"?

[Anonymous]

I was joking around with a girl during a lecture, and she went along by laughing and saying "Oh shut up!". She didn't seem mad at all because she had a big smile and was laughing, so is this a sign of interest or flirting?

[Izzex3]

I do that all the time and I'm not flirting.
I do that with girls too...
Doesn't really mean much besides the fact that i found what that person said funny and I'm saying "shut up" because that's just how I talk to people.

[MosaicMind]

I flirt like that, but she may just find you hilarious.

[emerald77]

She's just laughing... I don't think that means she's interested.