We had originally accepted about 4000 - although our goal has always been to make our MOOC as much about "open" as we possibly can. Our own misstep has caused us to accelerate things.
It actually happens dozens of times per year on a one-off basis, usually with college coaches telling recruits they've been accepted when the admissions office has only provisionally accepted them.
Actually, we just literally reversed the SQL queries for the emails we sent out for accepted/rejected companies – and then didn't immediately realize our mistake.
It's been a pretty tough day here at YC but we're all really happy with the final decision we came to!
How many had you originally accepted? (And thus, how many have advisors?)