"Facebook is being cited as a major factor in marriage breakdowns. More attorneys every year are using the site as evidence in divorce proceedings. An online study from a United Kingdom website found Facebook to be the driving force behind a third of divorces in which unreasonable behavior was a factor."
"Attorneys, Pastors see rise in divorces linked to social media"
"...people are looking up old flames or finding new ones in common interest groups on Facebook and other sites like it."
(My wife and I know a few people this has happened to).
I found this interesting...though not incredibly surprising.
http://www.ky3.com/news/ky3-attorney...,7155518.story