Yes, the legal age to join Facebook is 13. Since there is not a viable to make sure that only children over the age of 13 are joining, there are a lot of younger children on Facebook. Sometimes these children have created profiles with parents/guardians who consistently monitor its use. Other times these profiles are created more secretly. There are some important things to keep in mind in either situation.
First of all, children in the age range 13-17 are under certain protections on Facebook that adults are not given. "Everyone" settings are not as open for children younger than 17, for instance. Their accounts are not listed with search engines like Bing or Google, though they can still be searched for through Facebook unless the settings are changed by the user. Minors are not able to receive messages from people outside of their friends of friends network, but that does not promise safety. After all, just because one child is careful about adding people they know and can trust doesn't mean that everyone on that person's friends list is equally careful. All of these settings can be modified to stricter settings through Facebook by the user.
Secondly, children are creating a digital footprint when they interact online through social media. It is easy to think that since they are "just kids" they are safer from having to worry about their digital footprints, but that is nowhere near the truth. Colleges, employers, and other agencies can and do check social media before making decisions. While this does not happen all the time, it does occur frequently. I have personally known several people who have been fired or put on probation during employment for what they had posted online. The reputations of colleges and employers are affected by those who are a part of them and clearly they want to have the best image out there that they can. Children and adults both need to be careful about what information they are sharing online through Facebook. Status updates, pictures, and videos shared connect to the outside world. Whether it is bullying or oversharing, real life consequences exist.
Third, it is extremely easy to view what is said or done online as not really being done in a way that matters. This is something adults fall prey to as easily as children do, and so we must be vigilant in making sure children develop a more mature understanding of their responsibilities online. Having worked in customer service by phone and email, I am quite familiar with how much meaner people can be when they do not have a real person standing in front of them. It is vital that children understand that the people they interact with online are real people with real lives. Harassment is extremely common on the internet, and Facebook is no exception. Prepare your children for how you want them to handle situations when they are being harassed or cyberbullied so that they can work through a good path toward resolution. (Click here for tips!) At the same time, talk with them about what is appropriate for them to share on sites like Facebook and what is inappropriate.
The most important aspects of keeping children safer on Facebook are being vigilant about checking what they are posting and developing plans with the children about how to handle tricky situations. We talk about all of these things at school, but the more they can connect this knowledge to their families' expectations the better the information will stick, and the greater meaning it will have.
READ MORE at PCWorld: http://www.pcworld.com/article/206683/how_to_keep_your_kids_safe_on_facebook.html
(Information taken from link above, image from Yahoo! UK and Ireland Lifestyle.)