[biztos]

Doesn't the tax usually come when the consensus about the societal harm carries more weight than the money produced by that harm?

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.

[ajmurmann]

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"