Perhaps your coworker googled about backpacks after the conversation, and facebook knows you spent some time together just before that and put two and two toget

Perhaps your coworker googled about backpacks after the conversation, and facebook knows you spent some time together just before that and put two and two together so to speak. I'm sure most of the time their algorithms make guesses like that it doesn't result in anything relevant, but you don't notice those ones. If this cross-referencing of other people's searches is something that they're doing, though, that's concerning too. I don't want my partner to see ads for a gift I'm surprising her with because a facebook algorithm is guessing she might be interested in ads about things I've googled.