Venn Diagrams (not just something to forget from grade school)

15 Venn Diagrams To Explain The Internet’s Fascination With Venn Diagrams
http://nextround.net/2010/03/16/15-venn-diagrams-to-explain-the-internets-fascination-with-venn-diagrams/?utm_source=feedburner&utm_medium=feed&utm_campaign=Feed:+nextround+(NextRound.net)