That's alway the question when listening to authors/bloggers: do they just write well? Or do they actually know what they're talking about? One of the reasons I love Stack Overflow was that it was a validation of many years spent listening to Jeff and Joel: turned out they do know how to create wonderful (and very successful) programs.
YCombinator does seem more successful than you mention though: they've turned out a lot of companies that, while not always huge, are making money. A few of them are even game-changers in their industries, like Scrib, Posterous, Justin.tv, Dropbox.
YCombinator does seem more successful than you mention though: they've turned out a lot of companies that, while not always huge, are making money. A few of them are even game-changers in their industries, like Scrib, Posterous, Justin.tv, Dropbox.