One of my customers has his website runned under wordpress. I suggest him to start an affiliateprogramme and pay the affiliates per lead. He is in the tourismbusiness and not really selling a product online. Is there an affiliatesystem what i can integrate in wordpress so we can follow which customer comes in by which affiliate ? He will pay per lead : if customer comes in and fill in the form, makes a booking after a few weeks, then we like to know by which affiliate he came on the website first. So we can connect lead -> affiliate and pay the commission.