I know it's not the "check-it-dawg" sign, but I dont think it's hang loose either. Hang loose is all like:
\../
( \)
So I don't think its hang loose I'm talking about, but oh well. Anyway...
One day, some hippie was standing around, giving another hipped the good ol' thumbs up, when he realized something: "Hey, maaaan.. This is like...so totally uncool. I'm gonna like...compleetly change it and make it cooooool..." so, lo and behold, he stuck out his pinky.
When the forces of pinky and thumb combine, you get... DUN DUN DUN!!! The check-it-dawg sign! (or CID)
The other hippie, who was driving through a feild of wild flowers with his van belching out toxic gases into the atmosphere (not that I care, but they are supposed to) he sees newfound hand signal. The hippie is so amazed that he crashes into a tree and explodes and a giant mushroom cload appears above the area and everything within a 50 mile radius is disentigrated. Some guy 50 miles away got his brains blown out by an airborne billiard ball.
Then, in some small Wisconsin town, 1572 miles away, someone else did the CID for no apparent reason, and now it's become popular. The CID is the totally cool and hip thing. Everyone does it. Yes, even me. I mostly do it jokingly though. Not like I think it makes me look cool...
I'll go back to watching myself doing the CID in the mirror repeatedly...
~Hippies secretly invented the CID.~
Back to further enlightenment.