Way back when, Twitter very clearly stated the minimum age requirement for anyone signing up for a new account on the social network: 13.
Our Services are not directed to persons under 13. If you become aware that your child has provided us with personal information without your consent, please contact us at firstname.lastname@example.org. We do not knowingly collect personal information from children under 13. If we become aware that a child under 13 has provided us with personal information, we take steps to remove such information and terminate the child’s account.
Twitter doesn’t ask your age when you sign up, but Facebook does, and on Facebook the minimum age requirement is a hard and fast 13. It’s the same number on Instagram, Pinterest, Tumblr, Reddit, Snapchat and Secret, too.
Curiously, the minimum age on LinkedIn is 14. On WhatsApp it’s 16, and on Vine it’s 17. Some platforms, such as YouTube, WeChat and Kik, have a minimum age required of 18, although kids aged 13-17 can signup with parent’s permission.
Check the visual below for more social media minimum age requirements, which comes courtesy of Linneyville.