How does Google Analytics tracks users?Each user is tracked as unique user? I have a doubt about a goal flow in Google Analytics. I'm working on an ecommerce site. I set the goal as reach the "thank you" page after purchasing something. Before reaching the thank you page, users have to complete a checkout process. My doubt is about what happen if a user leaves the checkout process and comes back to site for add to cart another object and then returns to checkout and completes the order? What do I see on the goal flow? 2 entry in the checkout process (the first access and then the second one, after the user has added something to the cart) and 1 abandonment? I want to know if the user which has leave the checkout process and the user which completes the order is the same user. How can I track this?