Answer:
Answered below.
Explanation:
I made a search for a product on an online grocery store. The search results came in and I bought the product. On subsequent visits to the grocery store website or on browsing other sites, I had special advertisements pop up. These advertisements were suggesting products to me similar to the one I bought on the grocery store. It was a targeted advertisement that had been sent based on my recent searches and purchases on the site. So I knew that was a filter.