Most people don't know the extent to which companies track them across the internet and their devices. It really would be better described as "stalking" given that there is a clear intent by most online platforms to be as stealthy as possible when it comes to their data collection activities.

> Facebook knows a lot about you not because it's tracking you, but because you keep posting things to it.

That's not at all true. People who have explicitly chosen to _not_ have a Facebook account still have their data sucked into the maws of Facebook's data collection systems. [1]

> Cookie tracking is an alternative way to build up an effective advertising profile that is decentralized and anonymized

Cookies cannot possibly be used to build up any sort of decentralized "advertising profile" across the internet - either you allow third-party cookies for tracking and the advertisers become the centralized data collectors or you don't and the cookies don't really provide any information that a website couldn't already collect (and which, critically, wouldn't be useful to produce an advertising profile for anything other than a single website).

> [..] which I think has some value.

Value for whom? It seems that you're very interested in talking about the value of data for those who collect it and are completely disregarding the value or cost to the people who are being tracked.

[1] - https://news.ycombinator.com/item?id=5921092