Disable Third party Cookies in Google Chrome
Third party cookies are used by advertising and marketing companies, among others, to follow your usage of the web-at-large so they can better determine your demographic and target their advertising better.
Personally, I don't care for this, and I use the AdBlock Chrome Extension
anyway so I don't even see the ads. There's no need for this information to be tracked, though, and fortunately there's a way to turn this behavior off in most major browsers. Linked here is an article that shows how to do so for Chrome.