I agree, the idea may be insight to the creativity of the start-up, but it's the implemenation and execution that will make or break it. That's why (taken from app):
"your idea is important too, but mainly as evidence that you can have good ideas. Most successful startups change their idea substantially.
We're more likely to fund people we know are smart..."
It's the people that are smart, creative and determined that will do well (IMHO).
As has been said before, if you don't think you can win the race against someone else with the same idea, that's not very promising for you. You need more confidence (but not blindingly so), skill and determination to succeed.
many people try to pass the concept that "ideas are cheap". Yes, they don't worth anything without good execution. But, lets get serious. No matter how anyone want us to believe, good ideas are not cheap and giving birth to good ideas comes after struggle and effort.
We don't make any formal promise about secrecy, but we don't plan to let anyone outside Y Combinator see these applications, including other startups we fund.
I thought this was going to be a thread about what people do to continue their StartUp after they are rejected. It could have been an inspirational story about striving through rejection and building something good.