My friend opened a facebook account(free) in order to view someone's pictures at that someone's urging. He had no interest in becoming married to the thing so he created a false name so that no one he knew would try to befriend him.
For if you go out there with your real name, you'll start being contacted by people you know now and knew from high school, etc. However, he linked it to his real email address(it is not shown, safe right?) Facebook allows others (who have your email address in their electronic address books ) to easily link the address books and search for people they know via their email addresses. End result: He now has 138 friends on facebook.
If you are going to join facebook to view relatives' videos and don't want the others that you know to know that you are a facebook member. Create a false name and create an new email address to link it to and don't tell anyone about that email address or use it to communicate with anyone.
Facebook is the best friend of those who in an earlier time, would have had to drag the projector and screen to their friends' houses in order to show them the slides of their trip to disney world. These are the same people who urge you to join so they can bombard you with pictures, videos, as well as urge you to join their pet causes like united way , walk for cancer etc.
Also, employers generally are given email addresses from their employees and they can easily check what their employees or potential employees are up to if they (employers and employees ) are members of facebook and the email address is the same as the one the employee used to open the account. Most of the time, the employer would still have to be granted friendship status to view the whole contents of a facebook page, but sometimes, the facebook account holder , for whatever reason, lowered the privacy settings, and as a result anyone can see what is going on on that person's facebook account