I mean, the same reason why you'd want the newest of anything. Stuff on the top gets out of date. Even in the context of a comment thread, I'd want the latest c

I mean, the same reason why you'd want the newest of anything. Stuff on the top gets out of date. Even in the context of a comment thread, I'd want the latest comment in the thread, etc. Not to mention with threads you waste time reading things over and over again.