It's not a YC company. "Launch HN's" are one of a couple of perks reserved for YC companies. "Show HN's" are open to all comers, but only if you have an app people can play with right away (this is more of a landing page), and they're not ranked the same way normal posts are --- this post is doing great on its own, so their choice not to do a "Show HN" has paid off.