I recently found Dave Neal's relatively short opinion piece on the UK tech news site, the Inquirer, that explains social networks very well. The post is aptly named, "Privacy is your problem." See: http://www.theinquirer.net/inquirer/opinion/2163313/privacy
Neal explains [emphasis added]:
Managing a Facebook account is something of a full-time job. The company has a history of changing its privacy policies and launching applications that enroll you in some marketing and sharing exercise without your permission. This means that you must hover over your Facebook privacy settings like a hen worrying about its eggs.
It doesn't stop. This month Facebook gave its users, almost a billion of them, around a week to digest proposed changes that include among other things the renaming of the Privacy Policy to the Data Use PolicyIt makes more sense when you remember that social networks - all of them - are in the business of gathering and selling your private information to others - small businesses, large corporations, governments or just about anyone with the right price of admission. They're not giving you anything for free. You have to agree to give them something they value very highly - your own privacy - in exchange for the so-called services they provide.
If you someday run into a "privacy problem" some day because some potential employer demands you provide your Facebook or other social network password and user name before you are interviewed or hired for a job, that breach of privacy is not Facebook's, Twitter's or Google's problem, it's entirely your problem.
Guy Kawasaki once famously said, "Advertising is when you tell people how great you are. PR is when someone else says how great you are. PR is better." What do you do when someone deliberately puts "bad PR" about you that gets connected to your Facebook page or elsewhere on the web? What if someone hacks your Twitter account? What if it's just mistaken identity like the case of a Japanese man with the same name as a man connected with a serious crime?
Sometimes you get much more than you ever wanted or originally bargained for. I still think social networks and privacy issues could get very expensive before the problems are resolved. If you eventually have a problem with Facebook, I can just about guarantee that neither Mark Zuckerberg nor 844,999,999 other people he uses won't even care. It will be entirely YOUR problem.