This is just something I picked up some time ago while attending Łukasz Olejnik's PhD defense "Measuring the Privacy Risks and Value of Web Tracking".

He basically said that the problem with the advertising market form a privacy perspective is not the advertising itself but the tracking and profiling that comes with it. Obvious as that might seem, in my mind I had always thrown the two into the same pot, probably also because after years without a TV or thelike I am easily annoyed by any advertising.

But this simple insight leads Łuskasz to another one that is more profound:
Getting rid of the ads won't automatically solve the privacy issues.

Subscription-based publishing is one of the alternatives to advertising and often presented as more privacy-friendly. But what would happen if this model actually got adopted on a larger scale? Most probably, according to Łukasz, third-party services would quickly emerge to handle the subscription-management across sites. And just like that there would a very similar situation as before: A handful of people/companies would know who pays for which subscriptions, reads which articles, loads which images. Just like today's advertising industry they would be able to track and profile through cookies and all other means available. It would just look less annoying because of the missing ads.