GitHub was founded in San Francisco in 2008 by Tom Preston-Werner, Chris Wanstrath, and PJ Hyett as a community for developing and managing open source code using Git—the independent version-control software created by Linus Torvalds.
A little over a year after launch, the company had gained its first 100,000 users.  In July of 2012, GitHub secured $100M in venture capital from Andreessen Horowitz, a massive bet and vote of confidence for a software company at that stage.  This investment, the firm’s biggest to date, resulted in a $750M valuation.  That same year, Forbes named GitHub one of the Top 10 Tech Companies. 
Repositories on GitHub 
As of January 2013, GitHub had grown to ...