Almost all teenagers are hooked up to mobile services. The smartphone is the single device of communication, dominating the lives of the 13 to 17 years old.
Parents and teachers might bemoaning the digitalized lives of our children. However, the reality is, that for adolescents who have to find their place in society, to difine their identity, and to build their network of relationships, backing off from mobile communication and opting out of the platforms of social exchange is not at all an option.
The pervasiveness of mobile services in the lives of young people makes it impossible to neglect privacy. The platforms will have to do much more than just secure access via password or multi-factor-authentication. The data as such has to be made inaccessible for abusers.
Differential privacy regimes with strong cryptography, using homomorphic encryption and zero knowledge proofs lead the way.
A lot of useful data on how teenagers use mobile services can be found in this recent report by Common Sense Media:
https://www.commonsensemedia.org/research/social-media-social-life-2018