This is how we monitor how many unique visitors come to your website. We can see where they come from, which page they land on, which pages they have looked at and how long they have stayed.
We can also do end-to-end tracking. So if someone buys a product from your site we can back track to see where they came from, what search phrase they used in order to find you and/or your product. This enables you to implement more focussed marketing aimed at that particular search phrase.