I recommended this class to a friend of mine, she applied, but the day of acceptance came and went and she never even got a rejection email. I emailed Ned and never heard back either. It seems that all they managed to do was add her to their mailing list. So I cannot recommend them anymore for their way of dealing with applicants. Simply not responding is rude and unprofessional.
This is not uncommon. Though this is a great time to mention that YC sends pretty good rejection letters (we see these every batch, e.g. https://hackernews.hn/item?id=3180243):
We're sorry to say we couldn't accept your proposal for funding. Please don't take it personally. The applications we receive get better every funding cycle, and since there's a limit on the number of startups we can interview in person, we had to turn away a lot of genuinely promising groups.
Another reason you shouldn't take this personally is that we know we make lots of mistakes. It's alarming how often the last group to make it over the threshold for interviews ends up being one that we fund. That means there are surely other good groups that fall just below the threshold and that we miss even interviewing.
We're trying to get better at this, but the hard limit on the number of interviews means it's practically certain that groups we rejected will go on to create successful startups. If you do, we'd appreciate it if you'd send us an email telling us about it; we want to learn from our mistakes.