I'm pleased to see that this extension sends only the hashed URL to its server, so you're not giving away your full browsing history in real time:

    var url_hash = hex_md5(tab.url);
    xhr.open("GET", "http://hnd.mfairley.com/" + url_hash, true);

https://github.com/michaelfairley/hnd-client/blob/master/bac...

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...

I've just tried this one and it's great! It's simple, unobtrusive and smart: a logo in the address bar indicates that the post is already on HN. If you click it you're taken to the comments page. Neat!