Density of startups. Density of innovation. Density of entrepreneurs. Density of knowledge being shared. Density of events. 

 
Density, most entrepreneurship experts say, is key to a thriving startup community, one that is supporting and growing startups at all stages, attracting capital from inside and outside of the community and importantly, creating the collisions between community members that prompt deals to happen and connections to be made. 
 
Today, American Underground, the network of startup workspaces in downtown Durham and Raleigh (and parent of ExitEvent), releases its first annual report, revealing double the density of a year ago, 323 new jobs and more than $40 million invested in AU-based and affiliated companies. Early 2015 expansion to two more floors on Main Street in Durham will let the network expand from 180 companies to more than 200. 680 people work in the three spaces today.