Does HN even track how many people view the link? As far as I can tell, there's no JS on the home page other than the not-even-AJAX powering the upvote and downvote buttons, and they're not using <a ping>, so I'm not sure how that information would get back to the servers.
You could simulate it by recording its position on the front page for each impression. Assume that higher positions on the page are seen more. Then your metric is something like upvotes per position-discounted impression.
On the other hand, I'm not sure that dang would get much value out of this kind of metric unless he was trying to tune the ranking algorithm or something like that.
