I love reading Hacker News comments, but they're kind of a pain to follow once you get a few levels deep in a given thread. This is worsened by the (unusually large) average comment length on HN, which makes even a single comment take up most of your screen.
So I took a few minutes to write this simple Safari extension that lets you collapse and expand comments à la reddit. Enjoy!
Download: https://github.com/fletom/HNCC/raw/master/HNCC.safariextz
Side note: The Hacker News source HTML looks like it was designed specifically to infuriate hackers. Everything is levels upon levels of nested <table>s. Child comments are actually sibling elements with a progressively larger <img> spacer before them. A comment body is a <font> element, but a reply link is a <p>. Abandon all hope of sane markup, ye who enter here.