There seems to be quite some confusion around "tracking" and "tasteful" ads. Reality is, "tastefulness" is mostly a personal feeling based on relevance to the user which usually is a direct consequence of tracking (and taking the right action on it). I'm not talking about intrusiveness, which is a whole different UX issue and the only thing I think we all agree on.
But from all my experience in AdTech I don't think there's a single ads provider that "does not track", as it's basically the same as having a store that does not have a cashier's desk. "We don't track" is simply a big lie.
But tracking isn't black and white. At least, networks will track impressions and clicks, otherwise publishers won't get paid. But then there's Cookies. Advertising IDs. Audiences. You can even break it down on the individual user level. The biggest problem is simply responsibility and where to stop. Most large ad networks enforce responsibility by mandating minimum sized audiences by now, but with RTB it's possible to break down the last barriers.
The ecosystem is mostly based on trust in the advertisers right now and only the worst offenders get pulled, but mostly after the fact.
Marco made a good choice by not even trying to be judge, police and policymaker in the same person. It's an impossible task to begin with.