While I welcome the change, I do not think this will bring any additional accountability at all. It's a minor feature whose presence isn't apparent to most users, and aside from those paying attention to this post, most users will probably not be cognizant of how it works vs the old way. IMHO, we have to rely on other mechanisms for quality posts.
I would support testing this option. Every once in awhile, especially during contentious threads, I'm often curious to know who booped arguments for one position or another.
I think there is some accountability, but not a lot. The problem is, to find out who shared a comment, you need to travel to the chatter page and look for that comment (at least that's how I understand it). I know I personally don't spend too much time on the chatter page, so I suppose this won't affect accountability much, at least in my mind. Fair point ecib.