Currently, we have the option to click on 'favorite' to add submissions or comments to a publicly visible list. Occasionally (a couple times a month?) I do this for comments that I think are excellent: https://news.ycombinator.com/favorites?id=nkurz&comments=t
Some other users do the same, but I don't really know how many, because there isn't really an interface to explore this. It looks like about half the top of the "leaders" list make use of this feature, although in some cases these might just be accidental clicks.
Anyway, it would seem like there should be some great way to make use of this information, but I don't know what it would be. A simple list of recently favorited comments? Marking on the comments that have been favorited? Just more prominence to what a user's favorites are?
Probably there is some even better way: How can we make better use of HN's 'favorite' feature?