Ask HN: What does it mean if a post doesn't show up in the Show HN tab?

The Show HN heading is confusing. Those are just the posts with the highest number of responses. Look at the top of that page for a link to the newest posts which most likely aren't on the Show HN list yet if ever.

It takes a few hours too, but even if it doesn't get any votes it should still show up on one of the pages (click more at the bottom to browse more)

More time as a registered user