Facebook is a great utility if you want to stay in touch with friends and family, share photos, and see what other people are up to in their lives. It's free to use, of course, but that doesn't mean it comes without a price. If you're using Facebook, you're giving the company a ton of information about yourself which it is selling to advertisers in one form or another. And most people forget that when they download or sign up for an app or website using their Facebook login, that they're giving those companies a direct look into their Facebook profiles and some of their personal data. That can often include your email address and phone number, but frequently also your current location. If you're worried about your privacy, you can do two things: Opt out of ad tracking and - and this is sometimes rather alarming if you haven't done it in a while - look up the list of app companies that are logged in to your Facebook account. Read more: http://www.businessinsider.com/block-companies-tracking-you-on-facebook-2014-1#ixzz2rXJHivRy