I recall seeing a comment by Paul Graham somewhere to the effect that Zuckerberg set off his "founder detector" very strongly. This was after Zuckerberg was successful, admittedly, but it at least gives some suggestion that someone skilled at recognizing founders would have seen his potential.
Unless you saw something else, he was making a joke about having his own biases, not that he could identify Zuckerberg due to keen founder detection instincts:
> And Graham knew that he had his own biases. “I can be tricked by anyone who looks like Mark Zuckerberg. There was a guy once who we funded who was terrible. I said: ‘How could he be bad? He looks like Zuckerberg!’ ”
It wasn't a comment on HN, but during an interview (video) he did with MZ on YC. I don't have a link, but that may help.
Zuckerburg was telling a story of how he built a "social" website to share notes for an art history class, except he didn't have any notes himself but got everyone to share theirs so he could pass his exam. This supposedly was an early experience that started him thinking about social websites and sharing online.
PG then commented how his internal alarm was going off saying "fund him. Fund him", and how even though it was too late he can't shut off his brains instinct to sniff out good founders.
It's a story of how PG loves people who are "naughty" and know how to combine technical chops with an "screw over everyone around me to get ahead" attitude. AirBnB is the quintessential YC story.
