And what they are DOING with her?

If you have a smartphone, you also have a MAID, that is a “Mobile Advertising ID”. It is a unique identifier a phone’s operating system gives to its users' individual device. For Apple, that is the IDFA, which Apple has recently moved to largely phase out. For Google, that is the AAID, or Android Advertising ID.

Adsquare, a firm whose mission is to " empower companies to accelerate business growth by staying at the forefront of data-driven marketing", said in 2017 that “While being completely anonymous, and fully manageable by the user, MAIDs open the doors for advertisers to understand the fragmented user journey”.

In practice, lots of smartphone apps pass their user’s MAID to many third parties. This means that “Anyone and everyone who has a phone and has installed an app that has ads, currently is at risk of being de-anonymized via unscrupulous companies”.

After this post, please do go to MotherBoard to read how there is _“an entire overlooked industry”_ whose purpose is to do just that: link all the MAIDs collected by apps to a person’s full name, physical address, and other personal identifiable information (PII).

The result is, as MotherBoard explains in detail,

• to _“make a mockery of advertisers' claims that the truckloads of data about [people] that they collect and sell is anonymous”
• quite unlikely to be compliant with EU’s GDPR privacy regulation, and probably with other similar norm

The Motherboard piece mentions that some US politicians are presenting bills to forbid or limit this practice. Wherever you live, ask your representatives to do the same.