Visually mark new comments since last reload
When you reload the page, any comments that have been posted since you last loaded the page would be marked as visually distinct and new.
This is about the only thing I really like about LJ's redesign, personally, so I thought I'd suggest it over here. It could be done with either a hardcoded visual thing like LJ's, where a little yellow new comment button shows up next to new comments, or something that can be styled with CSS to be a dot or a different header color or whatever, that would just become part of the layout and people can choose to maximize or minimize how much it stands out.
It's especially helpful in very fast-moving posts where you want/need to track what everyone is saying, but need more context for each thread than tracking and only seeing what the immediately previous comment said with the newest comment, rather than seeing the last 10 comments in a straight row. I play a game on occasion where 5-10 people can make a hundred comments in an hour all on pretty much the same topic and you have to try to be following them all, and the last time I played it was oh my god so much easier with that feature. But it's the kind of thing that seems like it would be useful in almost any discussion you want to follow, but don't quite want to track the post for whatever reason.
Should be implemented as-is.
Should be implemented with changes. (please comment)
Shouldn't be implemented.
(I have no opinion)
(Other: please comment)