I collected all data between 2012-02-02 and 2012-02-03.

I tested all the 50 extensions/apps with news.ycombinator.com; I did not test all the other HN domains (news.ycombinator.org, news.ycombinator.net, hackerne.ws).

The order in which the extensions/apps appear below is not significant, except for the ones I tagged very useful, which come first. (broken < obsolete < 0 < funny < interesting < useful < very useful)

  1. Hacker News Amplifier 1.6 — Use this HN amplifier to see news with most points and comments at a glance, while preserving list order.
    Pop: 3 — Pro: It does it. Highly compatible. — Con: The icon could be better. — Very useful. (disclosure: I made it)
  2. HN Unread Comments 1.1 — Shows unread comments on Hacker News (http://news.ycombinator.com/).
    Pop: 59 — Pro: It does it. — Con: There could be a count on the home page. The color of the highlighting border could be an option. — Very useful.
  3. Hacker News Sidebar 1.0.7 — Hacker News integration for Chrome.
    Pop: 421 — Pro: It works. — Con: The sidebar doesn’t show up if a web page is on HN but it has still no comments. A page action could be a better handle for the sidebar. — Very useful.
  4. What HN says 0.2 — Shows the current page score. Click on icon to see discussion in Hacker News.
    Pop: 2 — Pro: It does it. — Con: Nothing. — Very useful. (similar to Hacker News Sidebar)
  5. HN New Comments 0.314 — Highlight new and edited comments.
    Pop: 12 — Pro: It does it. — Con: Options page lacks a title. — Very useful. (similar to HN Unread Comments 1.1)
  6. HNCommentTracker 0.2 — Hacker News Comment Tracker.
    Pop: 18 — Pro: It does it. — Con: Inconsistent: “new” and “unread” used interchangeably. — Very useful. (similar to HN Unread Comments 1.1)
  7. Hacker News’d! 1.0 — Lets you know if the page you’re looking at has been discussed on Hacker News (and lets you jump straight to that disucssion).
    Pop: 210 — Pro: It does it. — Con: Nothing. — Very useful. (similar to Hacker News Sidebar 1.0.7)
  8. Hacker News UX 1.2.2.1 — Hacker News improve user experience experiment.
    Pop: 371 — Pro: “About” feature very useful. — Con: There’s no option for enabling only what you need. It’s only home compatible with HN Amplifier.Very useful.
  9. Hacker News – Show Read Comments 1.0 — This is an extension to show you which comments you’ve already read.
    Pop: 7 — Pro: It does it. — Con: Nothing. — Very useful. (similar to HN Unread Comments 1.1)
  10. Hacker Friends 1.0 — Highlight when your friends post to Hacker News.
    Pop: 113 — Pro: It does it. — Con: Nothing. — Very useful.
  11. Shareaholic for Google Chrome™ 5.1.0 — The easiest way to share interesting webpages using Facebook, Twitter, Email, Gmail, Buzz, Reader, Bookmarks, and more…
    Pop: 64663 — Pro: All in one. — Con: A bit lengthy setup with so many choices. — Very useful.
  12. HN HideIt 0.5.4 — A collection of little utilities to make Hacker News browsing more comfortable.
    Pop: 30 — Pro: Nothing. — Con: Each reload causes a reset. Options are misleading, eg: “links” means “posts”, “hidden” means “grayed out”, … Some options are obsolete. Search box repositioning makes pages look broken.
  13. HN Reveal 0.21 — Reveals vote scores of comments posted on Hacker News.
    Pop: 14 — Pro: No options. — Con: It looks broken, it always shows “1 point by”.
  14. Readable HN 1.0.3 — HackerNews with a touch of beauty (Readability bookmarklet like styling).
    Pop: 102 — Pro: No options — Con: It makes everything much bigger. (Why not just zoom?)
  15. HN Search Suggestions 1.0 — Provides search-suggestions for Hacker News submissions and/or comments. (Type ‘hn’ in the omnibox and press tab).
    Pop: 7 — Pro: No options. — Con: Misleading instructions, eg: on my Mac, I had to use [h][n][space] instead of [‘][h][n][‘][tab] — Useful.
  16. HN Vote button 1.0.2 — Vote-up webpages directly from your browser’s toolbar!
    Pop: 2 — Pro: No options. — Con: Misleading icon. It looks broken.
  17. Show full domain on HN 1.2 — Show the full domain name on Hacker News next to titles.
    Pop: 7 — Pro: No options. — Con: It looks broken or obsolete.
  18. Flattehn 0.9.1 — Levels the voting field of HN by hiding usernames and points until you’ve voted.
    Pop: 8 — Pro: No options. — Con: It looks broken AND obsolete.
  19. Hacker News Collapsible Comments 1.1 — Adds reddit-like [+] and [-] links to collapse and expand comment threads.
    Pop: 258 — Pro: No options. — Con: Each reload causes a reset. I wish the default was all collapsed but showing the first line, gmail-like — Useful.
  20. Go Build Stuff 1.0 — Helps you concentrate on building stuff.
    Pop: 107 — Pro: No options — Con: Nothing. — Funny.
  21. Coley’s Hacker News 1.1 — Refreshes Hacker News every minute. All out-going links open in a background tab.
    Pop: 8 — Pro: No options. — Con: It looks broken.
  22. Noprocrast Enhanced 0.1 — This refreshes all idle (i.e. no keydown or click events) HN pages every five minutes.
    Pop: 1 — Pro: No options. — Con: What for?
  23. Mustard Gas (HN3) for Hacker News 1.1 — Mustard Gas.
    Pop: 4 — Pro: No options. — Con: It looks broken.
  24. Hacker News Modified 3.0.8 — Updated version of http://goo.gl/C7Kpp.
    Pop: 2 — Pro: It can save to Instapaper. — Con: Main icon is broken. — Interesting.
  25. HackemUp 1.1 — Keep track of what’s changed on Hacker News front page since the last time you looked.
    Pop: 106 — Pro: No options. — Con: It’s not compatible with HN Amplifier. It could just show delta of new comments. No help about icons. — Interesting. (similar to HN Unread Comments 1.1)
  26. Georgify 1.1 — Alternate CSS for Hacker News with a focus on typography and readability.
    Pop: 1530 — Pro: No options. — Con: It’s not compatible with HN Amplifier. Misleading documentation: It changes the DOM, not just the CSS — Interesting. (similar to Readable HN 1.0.3)
  27. Hacker News 2.51 — Displays recent stories from Hacker News.
    Pop: 688 — Pro: Nothing. — Con: Nothing. — Interesting. (similar to Hacker News Modified 3.0.8)
  28. Hacker News OnePage 0.8.2 — Provides users with the ability to browse Hacker News articles and comments without leaving the page.
    Pop: 343 — Pro: No options. — Con: It doesn’t remember my choices about what posts to show collapsed/expanded. It could show the Comments below the Article and not the other way around. — Interesting.
  29. Hacker News Hotkeys 0.1 — Gmail style hotkeys for Hacker News. Want Vim or Emacs style? Pay me or bother me :)
    Pop: 102 — Pro: No options. — Con: It’s using a browse action instead of a page action. Misleading documentation: h does not show help (the icon does). — Interesting.
  30. Hacker News Stack 0.3 — Focus on the really fresh and unread news in YCombinator – Hacker News. Relocate read items into the bottom of the website.
    Pop: 42 — Pro: No options. — Con: It works only if you leftclick on a post. The icon does nothing.
  31. Hacker News Reader 0.2 — Quickly browse Hacker News articles and comments.
    Pop: 1316 — Pro: Nothing. — Con: It’s an app (not an extension). — (similar to Hacker News OnePage 0.8.2)
  32. Hacker News Collapse 1.1 — Collapses comments on Hacker News.
    Pop: 106 — Pro: No options. — Con: Each reload causes a reset. I wish the default was all collapsed but showing the first line, gmail-like — Useful. (similar to Hacker News Collapsible Comments 1.1)
  33. Hackers News Reader 4 — Simplistic Reader for Hacker News.
    Pop: 690 — Pro: No options. — Con: It’s an app (not an extension). — (similar to Hacker News OnePage 0.8.2)
  34. Hacker News + 1.5 — Stylish Hacker News.
    Pop: 303 — Pro: No options. Home page really nice. — Con: Nothing. — Interesting. (similar to Readable HN 1.0.3)
  35. Readable HackerNews 2.3.4 — Stylish Hacker News.
    Pop: 412 — Pro: No options. Nice. — Con: Nothing. — Interesting. (similar to Readable HN 1.0.3)
  36. Reddit-Style Comments for Hacker News 1.3 — Adds a simple toggle to hide/show comments in discussion threads on Hacker News.
    Pop: 41 — Pro: No options. It shows #descendants. — Con: Each reload causes a reset. I wish the default was all collapsed but showing the first line, gmail-like — Useful. (similar to Hacker News Collapsible Comments 1.1)
  37. Hacker News Sorter 1.6.1 — Sort posts by points, enables search and linkify’s Hacker News.
    Pop: 26 — Pro: No options. — Con: Nothing. — Interesting. (similar to HN Amplifier)
  38. Hacker News Extended 00.1 — Framework for extending Hacker News.
    Pop: 4 — Pro: No options. — Con: No documentation. — (jko navigation)
  39. Submit to Hacker News 1.0 — Hacker news submit button for Chrome. Inspired by Phil Kast’s bookmarklet.
    Pop: 27 — Pro: No options. — Con: What for?
  40. Tweet From Hacker News 1.0 — Tweet articles directly from Hacker News.
    Pop: 60 — Pro: No options. — Con: Nothing. — Interesting.
  41. Hacker News platinum 8 — Hacker News extension that provides keyboard navigation based on reddit-platinum.
    Pop: 10 — Pro: No options. — Con: It could save scrolling time eliminating animation. — Useful. (jko navigation)
  42. NavigComments @ Hacker News 0.1.1 — Navigate through comments @ Hacker News. Any comment can be marked as read or highlighted, read ones can be hidden.
    Pop: 3 — Pro: No options. Marked comments are not lost on reload. — Con: It’s not possible to highlight on a Mac. — Interesting.
  43. Hacker News Hider 1.0.3 — This minifies/hides stories that you have clicked on at the YCombinator site: Hacker News.
    Pop: 7 — Pro: No options. Grayed out comments are not lost on reload. — Con: It works only if you leftclick on a post. — (similar to HN HideIt 0.5.4)
  44. Hacker News – Show Full Domain 1.0 — This is an extension to show the full domain (including subdomains) next to a link, rather than just the root.
    Pop: 128 — Pro: No options. — Con: Nothing. — Useful. (similar to Show full domain on HN 1.2)
  45. Hacker Sync 1.3 — Integrates Delicious bookmarking with upvoting at Hacker News.
    Pop: 28 — Pro: No options. — Con: Nothing. — Useful.
  46. Chrombinator 1.1 — .
    Pop: 15 — Pro: No options. — Con: Nothing. — Useful.
  47. Wompt Chat 0.1.7 — Wompt brings chat to all your favorite sites.
    Pop: 44 — Pro: No options — Con: Nothing. — Interesting.
  48. Popularity 1.4.1 — Shows how many times the current web page has been shared on Twitter, LinkedIn, Facebook, Hacker News and Google Buzz.
    Pop: 102 — Pro: No options. — Con: Nothing. — Interesting.
  49. Make Something People Want 1.2 — Redirects your list of distracting sites to makesomethingpeoplewant.org.
    Pop: 2 — Pro: Nothing. — Con: Nothing. — Funny. (similar to Go Build Stuff 1.0)
  50. HNdicator 0.1 — HackerNews Character Limit Indicator.
    Pop: 2 — Pro: No options. — Con: The smallest feature. — Interesting.