Oh they have much more than this.

Messenger asks nicely to upload your whole address book, and since half your college buddies clicked yes they know when and where you studied, and who you knew, and your parents landline thus some idea of their location (and how wealthy it is). Ditto your colleagues at each place you worked, who all still have your old corporate email, and some have newer info...

And that's before anyone posts anything on facebook.

And yet they can't show even a semi-related ad if their entire existence counted on it.

They have the data, yes. But they will ruin society before having any idea on how to use it.

Most importantly. They can not correlate that with my IP or my browsing history. So that information is beyond useless when trying to track me and only slightly useful for researching the society in which I grew up (which facebook isn't interested in anyway).

This is also true. I don't see how they're making money off their extensive knowledge about me.

When I make the mistake of buying something online in a browser logged into facebook, then I get adds for a week trying to sell me what I just bought... this does not lead to me buying another one! And all this strategy seems to need is basic cookies, not a shadow profile.

> Highly doubtful has any idea of even gender and age.

That depends if they know that you visit websites which are also visited a lot by other males between the age group of 20 to 30, then they can almost assume that you are a male between 20 - 30.

Big woop, what are they going to do with that information? They can "target" me with an ad meant for males in their 20-30s (which again, is just a very crude guess). Which will guaranteed to be a much worse fit than just targeting to the content of that site.

No tracking needed. Much better accuracy and return.

Big woop? you just said its highly doubtful they have any idea about your demographics, I explained you how they can easily do that and much more like know your race and income bracket.

The days of just targeting you based on the content site are over, now demographics and your search/click history plays a role too.

Because their accuracy is abysmal.

Maybe they have a few percent better accuracy than guessing at random. And that might be worth a few billions. But on an individual level they just don't have the slightest clue.

edit: State of the art tracking seems to be "look at what products user x has looked at, show the exact same product everywhere after he/she probably bought it".

Now if you do have and use a facebook account that is another thing.

> Because their accuracy is abysmal.

Can you give some sources for your claim?

Not really, but it is kind of obvious. I have a very weird setup which would be quite easy to fingerprint (probably a handful in the world and likely only one in my town uses my display setup for one). I am the only one using my devices and noone else is using my IP (and I don't switch IPs either) and I don't use any ad-blockers. Yet ad networks haven't got a clue, often even get gender wrong. (And as a male i interested in tech that should probably be the easiest scenario imaginable)

I guess the most tangible data point is when google allowed you to look at what google thought if you (gender, age, interests etc.) and how bad they are at it unless you actually use their services.

It is obvious they would be far better of targeting sites than users without accounts. But that is not where their competitive edge is so they downplay that. Also, I guess they are big enough to not care about people without accounts.

Don't forget shadow profiles based on data like others mentioning you on pictures etc.

They can not correlate that data with any form of identity with any accuracy.

They can't even detect fake and duplicate accounts, which would be trivial in comparison.

> They can't even detect fake and duplicate accounts, which would be trivial in comparison.

They almost certainly can, but due to capitalism, they have a business interest in not really removing these accounts.

That would be incredibly short sighted given the problem such accounts are for them and that they do go out of their way to ruin real accounts in search for them kind of reveals that they can't do it.

Much like the twitter bots to them, lip-service will be paid, action will be taken on some low hanging fruit so they look like they're working on the problem, but they will not make a concerted, legitimate effort to clean them up.