Just realised this:

Startup News: 150 posts

New: Top 50 posts

Best: Top 50 posts

Couple of questions:

1. Is the Startup News section a combination of New and Best?

2. What about the ones that don't show up under these sections? Are they permanently lost?

Startup News is the current hot stories. Best is stories with record-high votes.

Older stories are still around. They're just not linked to anymore. You can search for them at nycs.bigheadlabs.com

Is http://nycs.bigheadlabs.com/ the only way to access those posts that are not linked anymore?

You must have an API that gets you access to these unlinked posts, correct?

i = 0

while True:

    i += 1

    if not urlfetch('http://news.ycombinator.com/comments?id=%d' % i):

        break

# implementaton of urlfetch() left as an exercise to the reader