It would be useful to have a checkbox option similar to sifttalk's "Email me when someone leaves a comment on this post" when making comments. In theory someone could "favorite" the post, but it "favorite" posts carry a different semantics and don't seem to be used in that way.

For instance consider discussion on
http://www.videosift.com/video/Money-Banking-and-the-Federal-Reserve

I'm assuming that people posting such long informative comments would be interested in follow-ups, but only 1 person has the post favorited, so follow-ups would be lost