Imagine you visited an animal shelter, went to a pet store, and then visited your sister. Your phone, using location data or nearby Wi-Fi networks, can create "profiles" based on your actions:
- Visited an animal shelter — your phone assumes you are likely considering getting a pet.
- Spent more than 35 minutes at the shelter — the phone presumes you already have a pet and begins showing ads for pet products.
- Visited a pet store — purchasing pet products confirms ownership, prompting the system to display ads for relevant items.
- Visited your sister — she might also start seeing ads for animal shelters, as systems might assume you discussed this topic.
This data doesn’t require listening—smartphones collect enough information through location services, search queries, and app interactions.