Do you think if Zuck applied to YC today with Facebook as it was in 2005 he'd make it in? (Assuming the 'social network' landscape still looked like it had in 2005).
(Zuck comes to speak to the YC batch every year or so. PG used to say that when he talked to Zuck he'd find himself saying "whoa, we should really fund this guy". I had the same experience last time he came to YC.)
PG remarked that this was fitting answer for the "Tell us how you hacked a system" question in the YC application and added he has to constantly remind himself its too late to accept Mark into YC.