title: How do Third-Party "tracking cookies" work?
body: <p>I have read this question here: 
  <a href="https://stackoverflow.com/questions/8794981/how-do-internet-advertisers-use-third-party-cookies">How Do Internet Advertisers Use Third-Party Cookies?</a>
  on how third-party tracking cookies work, but am still very confused.
  I don't understand how if I visit Website A (a normal website with ads) how Website B (an advertising website) can assign my computer an ID, and then figure out that I was on website A, and other websites after it that have its ads.</p>