He knew about this.

Check pg announcement: http://news.ycombinator.com/item?id=1998376, almost 2 years ago.

Bingo. I figured many people either would either have missed that post, or have joined in the last 2 years. Either way, it seems like something people didn't know about and are happy to hear about it.

I think he may have read the code that makes up hackernews. If I remember correctly its open source.

That functionality is not present in the release of Hacker News that goes with arc here: http://arclanguage.org/install