"New" is ill-defined. One of the glories of trn is that each registered person has a file which keeps track of which posts and comments they've seen.
On usenet, this was possible because each post was shown one at a time in ascii, which was fast enough to work even over a 56K connection.
I don't think there was any way to make such a system to work on the web without JavaScript.
A scheme like yours could work with user-specified dates for collapsing everything prior and/or with collapsing prior to when the person signed out for those who don't just leave tabs open. It isn't nearly as elegant as having personal accounts that track everything a person has read [1], but might be better than what we've got now.
[1] trn included a "set unread" option.
It is ill-defined, yes. Hm...
Something similar to Google Reader might be nice, with the ability to 'star' items, and track read, and mark unread. Now that I think of it, how about letting us make an rss feed out of a custom search and just view it in your favorite feed reader? That might be fairly simple.
edit: Perhaps there is a simple or low-resource web rss feed reader that we can integrate with our message inbox? This is an example, I'm sure there are others as well.
Edit - please disregard this post
In the next month, the administrators of Less Wrong are going to sit down with a professional designer to tweak the site design. But before they do, now is your chance to make suggestions that will guide their redesign efforts.
How can we improve the Less Wrong user experience? What features aren’t working? What features don’t exist? What would you change about the layout, templates, images, navigation, comment nesting, post/comment editing, side-bars, RSS feeds, color schemes, etc? Do you have specific CSS or HTML changes you'd make to improve load time, SEO, or other valuable metrics?
The rules for this thread are:
BUT DON’T JUMP TO THE COMMENTS JUST YET: Take a few minutes to collect your thoughts and write down your own ideas before reading others’ suggestions. Less contamination = more unique ideas + better feature coverage!
Thanks for your help!