Script Summary: Remember which comments we've seen on LiveJournal and Dreamwidth.
This script remembers which comments you've seen on LiveJournal or Dreamwidth, and marks new comments with a link which says "NEW". Clicking the link selects that new comment. You can press the "n" key to go to the next new comment, and "p" to go to the previous one. Moving to a comment with the "n" or "p" keys will expand that comment if it's in a collapsed thread and the style provides an "Expand" link. On your journal and friends page, the script shows number of new comments on each the entry.
This script will store the user names and entry IDs of the posts you read on your computer, for obvious reasons. It does not access LJ itself for any further information than you've already downloaded when you loaded the entry, nor does it access any other sites.
This script works with most of LJ styles I've tried it with.
For more information, or to ask questions, please see my LJ entry about the script: http://www.livejournal.com/users/pw201/54000.html
To keep up-to-date with new releases of my Greasemonkey scripts, track posts tagged "greasemonkey" on my journal. You can do that from this menu.