Awesome for security. In order for this to work, the server-side has to keep a record of every single URL posted to HN, to be able to do a lookup of the hash. It's crawling the "/newest" page [1] once a minute [2]. Not sure how he handles situations where the worker goes down (do those posts just not get indexed?).

[1] https://github.com/michaelfairley/hnd-server/blob/master/upd...

[2] https://github.com/michaelfairley/hnd-server/blob/master/app...