"The nasty comment thread polarized the opinion of readers, leading them to misunderstand the original article."
"Instead of silent participation leading gradually to more active participation as one becomes more comfortable with the site, it seems the opposite is happening: mildly active users are now becoming silent users as it is easier to click 'Share on Facebook' than to post a brief comment."
The linked http://blogs.scientificamerican.com/a-blog-around-the-clock/... was also great.