I just read his 'infamous' post. He explains that he got accepted, then found out he would have to change his cofounders for personal reasons. This concerned ycombinator, which changed its mind and decided not to fund him because of all the sudden changes and the fact that it was affectively a single-founder company.
He glosses over it, but basically he appears to be a biz guy who had lost his technical cofounders for some reason and had his (idiosyncratic and evidently tenatative) acceptance rescinded.
Hi, Jon here! Actually, I'm the technical founder. I'm a Ruby on Rails developer originally (have commits in Rails itself). The other founders were graphic design and sales. For about 6 months (post YC incident), I was doing design, engineering, customer support, and fundraising for our seed round with just the help of my wife helping out with Community and writing.
http://joncrawford.com/post/20378314843/how-i-got-kicked-out...