Smartphones and advertising are the most harmful aspects. Having a place online you can connect to your friends is not really a problem, but if it's paid for by advertising it's then programmed to be addictive and manipulative, and if it's always in your pocket beeping at you, you never get away from it.

People used to give children beer for breakfast, and Coca-Cola used to contain cocaine, until we realised how bad those things were. It's about time we all woke up and realised that social media powered by advertising is dangerous. It should probably have a minimum age of 18 like alcohol does.