The link you share have an ID. With that ID we can see who created the link and who shared it. That is how we can count "Visitors gotten" and "Visitors given". There is also a of bit security going on to avoid spam. When a user clicks on the link we store their IP address so they cannot give you 100 visitors by clicking on the link themselves. If the link does not count when you visit it, you have probably already visited it once. We also check for crawling bots, too. Off course we do not count for those.