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Comment by oddlyaromatic | Hacker News Reader

>"what I've bought at <local supermarket> in the past year".

They get so much more than that. If you use a credit card at the store, the record now knows about this card, and any other credit card you have ever used while using that rewards program. This can all then be connected to other databases that track personal credit card spending in similar ways. A surprisingly detailed profile is quite likely to be out there on all of us, even if we are not always identified by name. If you have last 4 digits of a card plus zip code... You have a whole lot.

My memory is a little vague on the sources for this but I will try to dig up some relevant stories.

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I believe it is illegal (at least in some states) to use the card information for anything other than processing the payment. That is, I believe they cannot use it to track you and your purchase. This is one of the main reasons there are loyalty cards — to get you to explicitly consent to tracking.

edit: If they are allowed to track based on credit card, this would be a good reason to use Apple Pay, or some other payment method that generates a unique "card number" for every purchase.

I see. So, Google's use of CC data to track whether their ads work [0] is illegal, huh? I find it hard to believe they would announce doing it if so.

Edit: so you just want to hand over your info to Apple instead of some other big corporation?

[0]: http://www.slate.com/blogs/future_tense/2017/08/01/google_tr...

This goes nowhere. If you're using someone else's money to buy stuff, or a card that is a pointer through someone else's processing network, that someone will necessarily be able to see where it's being used.

You might as well ask for web servers to not see the IP address of people connecting to it.

I have yet to be worried about Apple advertisements and tracking. Any reason I should be?

Assign a GUID to card numbers. Use that GUID for tracking purpose.

Apple Pay does not generate a unique card number for every purchase. One number is generated when the card is added to Wallet. This seems to be a common misconception.

They may have been thinking about the transaction code. Every purchase generates a unique one-time transaction code for that vendor for a specific amount. That along with the Device Account Number is transmitted to the payment processor for the purchase.

Yet none of this is nearly as details as your web browsing history.

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