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"We don't sell any of your information to anyone, and we never will" (Facebook's data policy)

Here's one way of how FB has long been selling personal data to advertisers at scale, according to trade press reports.

I have long suspected they do, this is potentially huge #GDPR
So, FB shared individual-level data with advertisers or allowed them to query/link data involving device IDs via its 'measurement' partners.

This is 'personal data' as defined in the GDPR, and I'm sure FB didn't share it for charitable reasons, but received something in return.
I have long suspected that FB is directly sharing personal data with third parties for so-called 'measurement', but never had access to comprehensive info.

EU authorities must investigate this. This should be one more large GDPR case.

(AdAge article: adage.com/article/digita…)
A few tracking companies play a key role in this regard. They have similar data partnerships with other tech giants. All of them deserve regulatory scrutiny in the EU.

As long as they exchange data that relates to individuals they need a legal basis, and I doubt they have one.
One of Facebook's global 'measurement' partners is AppsFlyer, a company most people never heard of. They claim to track thousands of mobile apps and billions of devices.

We examined how they receive data in a recent study by Norwegian Consumer Council:
AppsFlyer claims to have a 'deep integration with Facebook' and states on its website:

"AppsFlyer matches deep Facebook ad analytics (e.g. impressions, clicks, cost) with rich in-app revenue events"
AppsFlyer also claims to enable 'bi-directional data sync' with Google:

Do the below docs mean Google and other so-called SRNs share personal data with AppsFlyer by letting it query click/impression data for certain device IDs?
support.appsflyer.com/hc/en-us/artic…
So, if Google and FB actually share personal data with third parties like AppsFlyer, what do they receive in return?

1) Their whole business model fundamentally relies on 'verification' through third parties, because nobody trusts them

2) They might also receive data in return
Many personal data sharing practices in today's real-time data economy are complex, dynamic and difficult to understand.

A single data transaction/exchange/query may not mean much. But at scale they can lead to massive effects that are far beyond what consumers would expect.
Apart from Irish trouble, it's crucial that EU regulators understand this and act accordingly.

I've long been calling to make Google+FB disclose their data partnerships. In case of 'measurement', they probably sell personal data. Equally relevant is how they buy additional data.
I also believe this is business as usual in adtech, and I agree there is a kind of disconnect with everyone outside the industry, including regulators. Or: hidden in plain sight.

Anyway, personal data sharing by Google and FB is a very specific issue.
And no, FB selling personal data to third parties is not a thing from the past.

According to the AdAge article, FB still shares data that 'shows what internet properties a device visited and which ad was the last one viewed' with 'measurement' companies:
adage.com/article/digita…
Btw 'selling data' can mean several things:

1) I'd say, FB/Google also *sell* data when they let others utilize it within their platforms

2) Disclosure to e.g. FB apps can imply a valuable consideration

3) The above issue is about selling personal data in the most narrow sense
This is how Adjust, a German firm who claims to track 32000 mobile apps, and also a FB/Google measurement partner, describes which personal data they receive from FB, including device/ad IDs:
help.adjust.com/tracking/attri…

German DP authorities could start investigating this right now.
Facebook's 'Data Use Terms for Advanced Mobile App Measurement' contain some interesting info about which kinds of data they share:
facebook.com/ads/manage/adv…

The previous version of those terms is not available anymore, but I took a screenshot a year ago:
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