If you're post is only on the new section and never makes the front page it will still get a bit of traffic.

http://abiekatz.com/2010/08/20/introducing-a-new-theory-the-...

It got 5 karma points and 29 page views from Hacker News.

So making the front page is very important for getting traffic from HN. I am sure this is the case for any social news site.