They already do it. Credit Card companies like MasterCard and AmEx have been selling data to advertisers for at least 8 years now. That plus all the data you can extrapolate from other sources can give anyone an accurate picture of your consumption habits.
Is this in their TOS? Do you know whether one can opt out? Are there any electronic payments schemes that (excluding the e-coins) don't share consumption data?
Their wording is very confusing for me - "To opt-out from our anonymization of your personal information to perform data analyses, please provide your Mastercard or Maestro payment card number below."
To me it sounds like, "we are anonymizing your personal info, but you can opt-out and allow us to perform data analytics using your personal info as it is."
This claims the data is anonymized. I honestly don't really care if my purchases are analyzed in aggregate. I understood GP to be more concerned about personalized data being sold to advertisers. I certainly would be.
