Comment levels haven't been noticeable in any decrease that I've seen.
Ok I've had to refuse a few "tactless" ones (1) and a good few duplicates...........and it's funny seeing when someone realises that they've duplicated a comment several times and then apologises equally as many times.
OK I'm warped .....but you knew that already
(1: DR's rule of thumb for commenting:-
If you're going to comment and criticise make sue that it's the type of comment you'd be happy to receive, don't be rude or insulting or praise yourself over others work 'cos that just makes people think you're a Douchebag!
)