I am interested in learning, from a general layman's perspective, how directed or targeted marketers achieve the result of having relevant ads show up in my browser. I am interested in the general nuts and bolts.
I look around for an herbal health supplement. This involves reading reviews and articles on the product and checking out vendor sites for price and availability. Once the buying decision has been made, I buy on line using Visa. Shortly thereafter, I receive and order confirmation and shipping & tracking info by email.
The next day, ad after ad from vendors selling similar products (supplements) magically appear in my browser.
How does that work?