It's certainly true that Facebook sells access to user data! Though you're right there's no API. Facebook doesn't make it easy, the technical resourcefulness of

It's certainly true that Facebook sells access to user data! Though you're right there's no API. Facebook doesn't make it easy, the technical resourcefulness of a grey/black adtech company are required. Much of this is non-obvious, even to web-savvy technical people. > I suspect what you actually mean is that I can run ads that are targeted based on aggregate user data ... so if someone clicks on my ads I know some general stuff about them based on my campaign targeting > but I’m certainly not getting a data dump about them, there’s no way for me to identify them, etc. An effective way to personally identify someone who follows a link and loads a page (and nothing else) is through browser fingerprinting [0]. Fingerprinting is more powerful and ubiquitous than many on this site realize. So, if a greyhat adtech company has data on a person's browser fingerprint history, then the Facebook targeting data can be _easily_ associated. Browser fingerprints should really, REALLY be considered as PII because that is how they are used. The data is relatively limited, but invaluable for future ad-targeting off the Facebook platform. And, if there's already substantial information in the database on a person, the high quality Facebook data can be used for quality control for other data sources. It's a tricky problem for Facebook to solve, but they have zero incentive to try. So they don't (that I've seen). ...and then there's the data they were selling via the developer interface. If anyone thinks Cambridge Analytica is the only example of this, I have a startup to sell them. One might notice that even Facebook is now branding the CA scandal as a 'breach' rather than 'system operating as expected', because of this criticism. Facebook may not have sold access directly, but by giving developers (and dark adtech companies) such unrestricted access to the data, Facebook pumped up their platform numbers which had a relative positive effect on the company's share price. This has all been conscious on the part of Facebook leadership -- there's enough smart people at Facebook, you can bet some of them raised red flags over the years. [0] https://arstechnica.com/information-technology/2017/02/now-sites-can-fingerprint-you-online-even-when-you-use-multiple-browsers/ https://arstechnica.com/information-technology/2017/02/now-s...