I've been aware of this for a while, but I swear to god, every time I see this I realize that the human brain is a marvelous machine because there is no way in hell I'd be able to keep track of all these social codes at once. Behold, the "Gay Hanky Codes":
http://alt.xmission.com/~trevin/hanky.html As said, this is sort of an old, well-known thing but seeing it all color coded like this is, again, a testament to human cognition (since I could never remember all that shit). I'm sure there's like a million cultural studies papers on it too. Cultural studies is probably one of the, um, disciplines that contributes least to the overall forward motion of the human race, I won't lie, but it is fun!