The one posted here: https://raw.github.com/nex3/arc/042990a55d8c880a0a88476eb52b169e47f35d32/news.arc is from 2006, it'd be nice to see a newer version that includes some of the changes the site had made since then.
The latest pg-release is at <a href="http://ycombinator.com/arc/arc3.1.tar" rel="nofollow">http://ycombinator.com/arc/arc3.1.tar</a> . It was released "only" two years ago (<a href="http://arclanguage.org/item?id=10254" rel="nofollow">http://arclanguage.org/item?id=10254</a> ) and runs on the latest version of racket. The repository you're looking at is an unofficial one that is much more active than pg's releases.
Have you tried looking at the github repo, here: <a href="https://github.com/nex3/arc/blob/master/news.arc" rel="nofollow">https://github.com/nex3/arc/blob/master/news.arc</a> the latest commit on that was in November 2011
I think he has stated before, or it has been implied by others, that releasing the source for hacker news might do more harm than good. There is a significant problem with voting rings now from the sounds of it. Hacker News has become a force that can greatly affect business and startups. If the voting ring people had the source, they might be able to find an exploit more easily that allows them to game the system. Clearly that would hurt Hacker News as a whole.<p>Basically, there are more black hats than white hats who would take a look at the source. YC is too powerful now.