Modern web browsers, by default, block third party cookies which that websites/companies cannot track you once you leave their website. Which is, of course, how real life works: once you leave a shop or place of business, they cannot track your every move for the rest of your life. That’s called stalking.
However, Adobe Flash does allow Third Party Flash Cookies and that’s why they deliver flash ads - to track your every move. This means that any website can check your Flash Cooke store. Thus when you visit an online shop, it can deliver a cookie to your Flash Cache. By providing flash ads on other sites, they can determine more information about you.
Here is a simple way to disable those Flash Cookies, because I don’t mind sharing some data, but not everything.