So we've all seen those spray-painted marks on the street -- usually they have a line, arrow and say "USA". As a planner, I've always had this nagging sense that I should know what they are.
Some brilliant editor at Wired apparently decided that it was time to figure it all out. A one-page feature, Urban Markup Language
, (Brilliant play on words) in the September, 2004 issue of Wired Magazine offers nine images of the most common forms of the graffiti, along with descriptions of what they mean.