[lugg]

Wild Speculation: typo in a limit clause. Probably only a few extra thousand got accepted but instead of weed them out they figured fuck it.

I'm going to also guess and say user accounts were created in a not easily rolled back way after the fact.

[kcorbitt]

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!

[rezultant]

Looks like you do mailing old (hackers) way - via SQL queries :)