Google's main source of profit is their advertisement business. The company has managed to become one of the world's largest by offering great services for free to its users, with the caveat of anonymously processing all their data to later leverage for the purpose of selling advertising.
To avoid criticism and "put users in control" of their privacy and security, Google has taken steps such as the release of the My Account Hub, back in mid-2015. By that time, the company stated:
"When you trust your personal information with us you should expect powerful controls that keep it safe and private as well as useful answers to your questions."
In a blog post this week, though, Google announced that some of its third-party partnerships now allow the company to track credit and debit card purchases and match them to specific online consumer profiles and Google users. Specifically, for the US, Google estimates it can capture "approximately 70% of credit and debit card transactions" through those partnerships.
Also, Google claims its recent upgrade to deep learning models has enabled the company to deal with scenarios such as "visits that happen in multi-story malls or dense cities where many business locations are situated close together". This new capability has enabled the company to collect even more data about its users, which is now being leveraged with the release of new tools for advertisers.
In the following months, the company plans to roll out Google Attribution, currently in beta, which features "store sales measurement at the device and campaign levels". This new advertisement service, in conjunction with those third-party partnerships, would allow advertisers to "match transactions back to Google ads in a secure and privacy-safe way". Such an accuracy level for measuring advertisement performance is unprecedented and could help Google further increase its ad revenues by attracting more advertisers to its platform.
Of course, Google ensures all the data is processed anonymously and by complex, patent-pending mathematical formulas. Those formulas would make it impossible for Google to know the identity of the real-world shoppers or for the retailers to know the identities of Google’s users, what the company calls a “double-blind” matching.
Unfortunately, those high-tech mathematical formulas are not for our eyes to validate that all those privacy claims are indeed true. But you can be sure that the chances are high that Google will know about your next card-based purchase.