A lot of people anecdotally believe this "they're listening", but I don't, since if it happens offline, it would consume a lot of power of the smart devices, and if it happens on the cloud, then the bandwidth and computing requirements would be gigantic and probably have poor ROI that it's not worth it. But maybe I'm overestimating those requirements.

Then again, I opened Instagram at a carwash once, and a few days later I got ads about car treatment products. I walked by an e-bike store the other day and stopped for about 15 seconds to look at the bikes being displayed, and a few days later Instagram started showing me ads for the brand. I thought Instagram or another Zuck-app was tracking my location, but I just checked and none of the Zuck-apps on my phone have location permission enabled.