Drupalcon

In 2005, just over 100 people attended the first North American Drupalcon in Portland, Oregon, followed by around 150 people attending in Vancouver in 2006, just over 300 people attending in Sunnyvale in 2007 (where the conference shared a billing with the Open Source CMS Summit at the Yahoo! Campus), about 850 people attending in Boston in 2008, approximately 1400 people attending in Wasington, DC in 2009, and then around 3000 people attending the San Francisco and Chicago conferences in 2010 and 2011 respectively.