The document summarizes attendance data from past FOSS4G conferences between 2006 and 2011. It shows line graphs depicting rising attendance numbers, with 902 attendees in Denver 2011 being the highest. Pie charts show the geographical distribution of attendees, with North America making up 76% and Europe 18%. The US alone accounted for 612 attendees. The document discusses the collaborative and educational nature of the conferences in bringing together the 'meeting of the tribes' in open source geospatial technologies. It provides information on the local organizing committee and sponsors for FOSS4G 2011 in Denver.