It takes every HN comment that links to another HN item, drops the dupe/previous discussion/related links, and uses Sonnet to decide which of the rest are actual recommendations. Then it ranks them by how many different people recommended each one.
The Dropbox comment is #1, which I guess is no surprise. Further down there's a lot I hadn't seen.
If you swap news.ycombinator.com for yrecombinator.org in an item link, you can see who recommended it.
Inspired by Karpathy's HackerTube: https://yrecombinator.org/item?id=50319510