Ask HN: Did YC accept anyone without an idea this round?

Clearly, at one point on the spectrum, it's people who meet a second before the application purely for the purpose of working on the application to fake their way into YC.

At the other end on the spectrum, people who have known each other for all their lives (say, twin brothers).

The former might on paper have great credentials (if I were going to pick a "fake" cofounder, I'd pick someone who has already built something similar, has a lot of accomplishments, etc., all things being equal. And, to a small extent, being able to convince someone like that to join your team kind of means something.

The latter would potentially join your startup even if he didn't believe in the idea, or have any real competence, etc., just out of familial obligation. But maybe siblings had a lot of similar experiences and both got interested in and involved with a certain tech early on.

It's even more complex with spouses. Say I'm a great musician, and I spend all my time with musicians, and really respect musicians and music. It's entirely likely my choice of spouse would be another incredibly talented musician. But, it's also likely that if people are married for other reasons, one might want to do a startup and then pull along a less-qualified spouse.

I think the sweet spot is somewhere beyond "met for just this project", at least if it hasn't been going for a long time, but "met for professional reasons", not purely social or familial ones. But it's probably a pretty flat region after that, where individual variations matter a lot more.