Inspired by Bloglines (*), which apparently in turn was based on work by Matt Kruise, I’ve added navigational key support to Planet Intertwingly and to the index and comments pages on my weblog.
Press ‘j’ to go to the next entry, or ‘k’ to go back to the previous entry. The space bar will page down the screen (I get that 'for free').
I’ve tested it on Firefox and IE. Despite following these instructions, the computed page offset always seems to be zero in Opera, rendering this script useless.
(*) Note: if you are an active Bloglines user, clicking on that link will have the side effect of marking all of your feeds as having been read. However, if you do go there, you will see that the bug I reported has been fixed.