I just found this on Boing Boing and thought it was very appropriate to re-broadcast. It is from xkcd: A webcomic of romance sarcasm, math, and language that is quite entertaining comic strip.

I think this map also reflects the nature of identity on the web...we show up in a lot of different places and need identities that work across them - with the freedom to link and de-link them. It also highlights how fundamentally identity is social and for engagement with people in community.

<img style="border: 2px solid #000000" src="http://imgs.xkcd.com/comics/online_communities_small.png"/>