For Salman Khan (of Khan Academy) to expand his project from his cousin Nadia (2004) to:

1. dozens of users (2005)
2. hundreds of users (2006)
3. thousands of users (2007)
4. tens of thousands of users (2008)
5. hundreds of thousands of users, quitting his job as a hedge-fund manager, getting $110,000 (from the interested spouse of a venture capitalist), an actual office, and a handful of employees (i.e., other than himself) (2009)
6. millions of users and getting multiple millions of dollars (from the Gates Foundation, Google, etc.) (2010)

took:  1. one, 2. two, 3. three, 4. four, 5. five, 6. six years.

By comparison, from my initial handful of business training sessions in September 2012 to the point of making my vaguely similar OurMus.Net a reasonable success (i.e., also on my own), I have:  six MONTHS!