BSides was born out of the number of rejections to the CFP for Black Hat USA 2009.
A number of quality speakers were rejected, not due to lack of content but lack of space and time.
Any constrained system must operate within the bounds to which it has defined itself. Conferences constrain themselves to the eight hours a day for however many days they run. Our goal is to provide people with options by removing those barriers and providing more alternatives for speakers, topics, and events.