I could have posted something that would have generated more traffic, but I won't.
Teens who frequently use Facebook have more to worry about than lost homework time. A new condition dubbed "Facebook depression" may affect teenagers who spend a significant amount of time on the social-networking site, researchers warned in the latest issue of Pediatrics Journal. The problem, researchers found, was that the popular website's constant feed of status, picture and message updates gave users a skewed view of reality, which could make vulnerable kids feel like they aren't good enough. http://www.nydailynews.com/lifestyle/2011/03/28/2011-03-28_teens_who_use_facebook_social_media_may_suffer_from_new_condition_called_faceboo.html
You don't have to be a teenager to suffer Facebook depression. Facebook will monitor a page calling for a third Palestinian uprising against Israel but will not remove it. http://www.jta.org/news/article/2011/03/28/3086590/facebook-to-monitor-intifada-page-wont-remove-it
And here is an article that did a good job of getting me depressed.