That's why the privacy policies are so important.
Nobody reads them, and even if they did, 90% wouldn't understand them and they'll just join "the party". The 10% that do understand... I bet less than 1% out of them won't join "the party"... which is actually the unwanted 1% (that's 0.1% out of those 100%) of critical thinkers that those sites/platforms wouldn't want joining "the party".
"Any site with the resources and desire to understand its visitors" might be closer...
Well... in general, make money off them (the users). There are exceptions, but they're so few, not even worth mentioning.
Remember, if the product's free (as in free beer), then you're the product

.
Up to a certain level, yes - pretty much any website these days does some sort of analytics on their visitors. What varies is the scope and level of detail.
Correct

.
How many sites do you think you visit in 18 months? That would bother to track the data? And somehow make it available to Facebook? And have the resources & infrastructure to do so?
About 500 sites... I don't have accounts for any of them... I'm blown away by the scope...
Doesn't really surprise me.
Well, I wasn't interested in tracking for financial purposes. I was more curious to know if there was a security benefit to see where an IP you found suspicious might be going with whatever it did on your site--after it left your site.
Doesn't really matter since bots/botnets can change/spoof IPs, so... don't really see any point in doing this... except maybe curiosity.