Chris Sacca talked about it in-depth on This Week in Startups a while back. From day one they told investors they planned to never sell. Chris Sacca didn't believe them but was in for the mission (and kept Kickstarter off his promotional material for a while because he wasn't sure about the return possibilities). Over time he believed the founders more and more that they wouldn't sell and they're in it for the long haul.

Similar story with Fred Wilson and USV.