But that should only help e.g. a web store to track you from the ad you clicked, which seems reasonable. It should not allow e.g. Facebook to link your activit

But that should only help e.g. a web store to track you from the ad you clicked, which seems reasonable. It should not allow e.g. Facebook to link your activity on a news site to your Facecbook cookie, because while you're on cnn.com, your browser is using the cnn.com-specific cookie jar for everything, including the like button?