9 points
It’s not just that either. Google knows who your family is. They know who lives with you because of location data. So any time those people search for anything regardless of whether they’re on your home network, they likely serve ads to whole families at a time when one person searches for something.
3 points
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This has been my theory as well, Google presumably knows when I meet up with a friend for lunch (I don’t know if they go to such lengths but they certainly have access to the data to figure it out), if my friend then starts searching for something related to our conversation afterwards, Google could serve me ads about it too, just inferring the topic of our conversation based on that
