I find this to be pretty interesting. http://thedrum.co.uk/news/2012/01/02/facebook-blame-one-third-uk-divorces-claims-law-firm Thoughts?
I think Facebook is the direct cause, but did the amount of divorces also rise? I hear about people having fights over the tiniest little things before they divorce, like the man not cleaning up his socks. If it wouldn't be about Facebook, it'd be about something else a week later.
According to my Sociology teacher, Facebook has accounted for one of the main causes of divorces in recent years. One of the main reason is adding or talking to ex girl friends on Facebook.
Facebook is just a way to converse with others, and a means of storing information for a few weeks before it becomes completely unnoticeable. It all comes down to the relationship between the two. (or more than two, for you polygamists) and what the person using Facebook posts.