Instagram | Mike Krieger & Kevin Systrom

Name: Mike Krieger, 25; Kevin Systrom, 27

Company: Instagram

Year founded: 2009

Location: San Francisco

2010 Revenue: Undisclosed

2011 Projected Revenue: Undisclosed

Employees: 4

Website: Instagram.com

Facebook: Facebook.com/Instagram

Twitter: @Instagram

Just after midnight on October 6, 2010, Kevin Systrom signed into his Apple App Store control panel. "Here we go," he thought. With a click, Instagram, the photo-sharing app he'd created with Mike Krieger, was open to the world. Beta users had been signing up for access for weeks, and now, with them all on board and posting photos, buzz was building at a rocket's pace. read more