Well, you should try to establish the societal cost of the negative externality and then tax at that level. The idea isn't to destroy the thing but to make it's price reflect its actual cost
Edit: "then cost" => "then tax"
Edit: "then cost" => "then tax"
Or at least enough weight to be competitive. Sin taxes have a way of permanently tying the sin (at some reduced level) to the general budget.
I don't think we're there yet. People can get plenty mad at "tech" without connecting the ad-tech dots.