Comments are part of the blogging ecosystem as far as I'm concerned, turn them off and the engagement goes out of the window, sure it might happen on Google+ or Facebook for that matter, but that's not really where the conversation should be in my mind.

Admittedly I do turn off comments on specific posts, i.e. reviews, announcements, or posts that hasn't received any comments whatsoever, but generally I like to keep comments on articles that I encourage engagement.

CopyBlogger's decision to turn off comments is just a way of them saying, hey we're big and bad now, we can do without the hassle of administrating comments on our blog, let's take the conversation elsewhere. That's just my opinion though.