Quora is a great resource for learning about how certain startups gained traction. There's even a specific topic geared towards it here: http://www.quora.com/How-Did-X-Get-Traction-1
Thanks for this, and I have read a bunch of them. I was more interested in some of the operational details and the data/numbers that founders can give.
Perhaps you can ask them directly? I know there are people who did , one example off the top of my head, someone asked how kickstarter got their initial projects, and one of the founders responded friend of a friend.