The map above shows the approximate locations of over 400 of the DrupalCon Barcelona 2007 attendees, based on the city or country they entered when registering for this year's DrupalCon. People travelled from every continent except Antarctica (maybe next year?) to visit the conference though most attendees travelled from Europe or the US.
If you're reading in an RSS reader, or if you prefer using Google Earth rather than Google Maps, you may want to load up the KML file, otherwise you'll need to move the map around a little to make Google Maps load all the locations for you.
(Sorry for all the pushpins. I was hoping to move beyond pushpins but the GeoCommons server didn't seem to like my file, probably due to the lack of attribute data in it.)