I always find post-mortems like these a bit strange. These founders are all able to develop some pretty convincing reasons why they failed (albeit in hindsight), yet show no signs of acting on it. I understand the feeling of burnout, I have a handful of abandoned projects myself. I've never been able to look back and say <i>that</i> is precisely why I didn't succeed though. Lessons learned is one thing, identifying the one factor that held you back is a bit of a stretch IMO.<p>Interesting side note: The first failed company, Verifiable, links to the sixth failed company, swivel, as an alternative. Apparently charting is a tough space.