Less Wrong Comment Highlight
Less Wrong has a handy feature highlighting comments made since your last visit. Unfortunately, if you didn't actually read all of the comments on your last visit, there's no way to get back the highlight it displayed then. Also, finding new comments requires scrolling, and who wants to bother with that? This bit of code aims to fix these problems.
See screenshots here.
Installation
Tested only on recent versions of Firefox and Chrome.
Firefox users: Install Greasemonkey and open lw.user.js in Firefox. (The 'raw' version, ie, this link.)
Chrome users: Install the extension! Or do it the hard way: save lw.user.js to disk, go to chrome://extensions, and drag the script onto the main body of the window.
Usage Tips
Clicking the [-] (only displayed if there is a nonzero number of new comments) will show or hide the list of comments. Clicking on an entry in the list will scroll you to it (provided it isn't already on the page).
You can edit the date displayed in the textbox, and the highlighted comments and comments list will update accordingly.