If someone were to say to you “I’m going to put this private photo of you, with all of your details attached, on a billboard in the center of London”, would you let them? The answer is very probably a resounding “No!”. So why would you not change your privacy setting on sites that can be viewed by millions of strangers?
It’s a common process for recruitment agencies and potential employers to scan over your social presence and search for anything that may be of detriment to your employment chances. It is also becoming more common for people to carry out the same process as a matter of course when connecting with you on LinkedIn.
As with any system that stores sensitive data, security needs to be set up to protect your privacy on social networks, otherwise anyone can potentially run a simple Google search to discover everything you do and say online.
Below are some great articles explaining how you can lock down your various social accounts and control who can, and more importantly who cannot, see your information: