When we get stories like this that get repeated multiple times on Hacker News (a few others spring to mind recently) it's a minor annoyance if you're an ardent HN reader but a significant indicator of what HN readers really find interesting on the whole since it's getting voted up each time by a different subset of users who hadn't seen it before.

Things involving novel presentations of algorithms and well presented 'undry' academic papers seem to do very well in this regard..