The Facebook button is disappearing from websites
cnbc.com
cnbc.com
Sadly some countries (Bulgaria, for example) are still running heavily on Facebook for all businesses that do not want to invest into a proper website.
Maybe there's an opportunity for a new company to take over those?
Facebook took off like email. In many respects, it's true value is network address book in my opinion. And focus should be on that, as opposed to building a social network.