while i am not denying in any way the severe dangers of the internet, i am unable to understand why allowing teenagers to access information is such a bad thing. I think that this attitude of totally sheltering kids is backfiring on us, and that the best way to deal with it is by educating teenagers in the proper uses of the internet (as it can be used as a tremendous source of information and benefit)
that being said, however, there must also be some level of control. Why not just treat the internet like yichud? no access unless someone else (who is responsible) is around