I will say that parents MUST be their friend at this stage, so as to be privy to whatever they are up to per time, and even know the sites they visit. You can then advise them appropriately. Because some are able to outsmart you when you set limits on their devices; they find other means through their peers. You just need to get them to understand your point and go along with you.
Another thing, the Internet is making youngsters millionaires! This is a scary thing when the young ones concerned have not already imbibed proper values. Lots are getting richer than their parents and guardians already and are fast dropping any dependence/reliance on them. Parents, please start the work before they become adolescents, and like the post ends, use your social media for good purposes only. Set the example you want them to follow.