If they are on different social media sites they should use different user names and passwords on each one.
You will know how it works and also be able to talk with them about it. Teach them that when they post information whether on Facebook or through email only share what they would want everyone to know.
Tell them not to reveal too much personal information online. Parents with teens should teach them some tips about using the Internet wisely.
Discourage teens from meeting and dating anyone online.
They should tell an adult when someone sends them inappropriate messages and photos.
On the positive side social media can be a place to share hobbies and common interests with other kids their age.
Try to get your kids to talk about their online social media activities if you can.