All of these things I mentioned in the most recent open thread, but since the first one is directly relevant and the comment where I posted it somewhat hard to come across, I figured I'd make a post too.
Custom Comment Highlights
NOTE FOR FIREFOX USERS: this contained a bug which has been squashed, causing the list of comments not to be automatically populated (depending on your version of Firefox). I suggest reinstalling. Sorry, no automatic updates unless you use the Chrome extension (though with >50% probability there will be no further updates).
You know how the highlight for new comments on Less Wrong threads disappears if you reload the page, making it difficult to find those comments again? Here is a userscript you can install to fix that (provided you're on Firefox or Chrome). Once installed, you can set the date after which comments are highlighted, and easily scroll to new comments. See screenshots. Installation is straightforward (especially for Chrome, since I made an extension as well).
Bonus: works even if you're logged out or don't have an account, though you'll have to set the highlight time manually.