You submit a single application, and include all your founders' Hacker News account names there. If you have multiple ideas, you submit multiple applications, o

You submit a single application, and include all your founders' Hacker News account names there. If you have multiple ideas, you submit multiple applications, one per cofounder, but each idea gets only one application. We're applying for YC summer - we've been updating and trying to fine-tune our application since we first submitted. I'd advise you to get what you've got submitted, and to spend the next day or two looking to perfect what you have.