I've seen people use this sign for "bullshit" and for "Texas Longhorns".
In football, it means, "second down".
I guess it could mean different things.
i have never seen it for bullshit, its rock on, or rock hard.
what hand "sign" are we talking about? what does it look like?
Just like the I Love You sign but without the thumb - so you see just the index and first fingers.
I see that used all the time for "bullshit" and, of course, "you rock" ... Depends on who you're talking to.
C'mon people, it's called Devil's horns! It originated with Ronnie James Dio of Rainbow and later, Black Sabbath.
I really must insist that you guys rock out more often. :P