When we go online we can be subject to targeted advertising based on our previous search history.

Some people are of the belief that their devices are listening to them, after they have received advertisements for products that they have simply mentioned out loud but have not specifically searched for online.

But, this phenomenon is more likely linked to the use of ‘cookies’ which are able to remember interactions you have online. This information can then be transferred into targeted advertising, by showing the online stores or other websites that you frequent as advertisements, and even offering up similar options to you based on your search history.

This may seem innocuous, and even potentially helpful, but goes to show that any information that you are willing to provide online can be used by others for many different purposes.

https://theconversation.com/is-your-phone-really-listening-to-your-conversations-well-turns-out-it-doesnt-have-to-162172