Oh boy. Yet another (perhaps the fourth of fifth) discussion of this.
Shame that MNHQ cannot seem to consider it more seriously. The last most recent thread about it had very similar comments from those who hate the idea, but plenty of other comments in favour, and while I personally don't use FaceBook, so would not suggest this be called a 'like' or 'dislike' approach, the 'thumbs up' / 'thumbs down' icons seem quite reasonable and does not prevent anyone posting comments too.
One problem with non-threaded discussion boards is that when you post your "I agree with " comment, unless you either quote part of it or show the date and time of it, you could be mistakenly supporting someone for one post when another later on offends you.
I have seen suggestions of it being for the lazy, and on the lines of dumbing down, plus the idea that it would lead to big ego problems, but have yet to see any firm comments from MNHQ about whether they would even consider it!
How can one prove there is/ is not a decrease in discussion ? Only by trying it out, something I'd really like MNHQ to do. They already have Facebook and Twitter buttons (now moved to the top of each page) and add features (which can be ignored if one wishes, for example, whether one uses 'bookmarks' or not).
Anyway, I'm not going over old ground again on this thread... plenty of arguments against it are forthcoming, but few are based on much more than levels of distaste about other websites...