[note this is a thought experiment - not entirely sure it's a good idea]
Forbid advertising in online services so as to change the incentives for those who create online services. Today the incentives in an advertising-supported world encourage tactics that addict and habituate irrespective of value received. In short, a world where "hijacking your attention" is the main business strategy. In a world where people paid for internet services, the focus would return to providing value to the user. As a metric on the costs of paid internet services, Facebook's revenue per user is a bit less than $2 per month. And that no doubt includes substantial expense to support the advertising infrastructure.