You can refer people to your profile or to any of your hub pages with a referral code included in the URL. To get this URL just go to the page you want to refer them to, scroll down to the bottom and click on "link to this page" - it will give you a URLwith your HubPages Referral Tracker included. When there, you will see that you can create and select different trackers. This gives you the ability to track different referrals. Presently, you can create up to 30 trackers, although that may change.