There is a risk that governments decide it is easier to tax what companies do, rather than more easily adjusted financial numbers - i.e. a similar approach to the tourist/bed tax being suggested to catch airbnb-style operations. I can see reasons why Facebook et al would (unofficially) welcome being required to charge their users a "subscriber" tax - they can pass the blame while putting payments systems in place that would make it much easier to further monetise their products^W users.
Biting the hand that feeds IT
