They were already using Google Drive and/or Docs data for ad targeting.
How do I know?
In 2023 I decided to lose some weight. I created a Google Docs spreadsheet titled "Weight 2023" and every day, added one line to it. I did not do a bunch of Google searching for weight-loss products or exercise machines, I didn't suddenly start buying supplements on Amazon; the only change I made to my online habits was to open a spreadsheet and access it every day, to track my daily weight and see whether my new exercise-more-and-eat-less routine was working.
Suddenly I started getting Play Store "recommendations" on my phone for fitness-tracking apps, weight-loss calculator apps, and so on. I had never gotten such recommendations before.
That's when I realized that yes, Google could tell what I was doing from the title of my spreadsheet and the fact that I added one line to it every day.
How do I know?
In 2023 I decided to lose some weight. I created a Google Docs spreadsheet titled "Weight 2023" and every day, added one line to it. I did not do a bunch of Google searching for weight-loss products or exercise machines, I didn't suddenly start buying supplements on Amazon; the only change I made to my online habits was to open a spreadsheet and access it every day, to track my daily weight and see whether my new exercise-more-and-eat-less routine was working.
Suddenly I started getting Play Store "recommendations" on my phone for fitness-tracking apps, weight-loss calculator apps, and so on. I had never gotten such recommendations before.
That's when I realized that yes, Google could tell what I was doing from the title of my spreadsheet and the fact that I added one line to it every day.