Marco Arment writes

Because of how the web and web browsers work, the involuntary data collection starts if you simply follow a link. There’s no opportunity for disclosure, negotiation, or reconsideration. By following any link, you unwittingly opt into whatever the target site, and any number of embedded scripts from other sites and tracking networks, wants to collect, track, analyze, and sell about you.
That’s why the implied-contract theory is invalid: people aren’t agreeing to write a blank check and give up reasonable expectations of privacy by clicking a link. They can’t even know what the cost of visiting a page will be until they’ve already visited it and paid the price.