Embodiments of the invention provide a fraud prevention method for a pay-per-click data processing system. The method can include receiving a click through for a link in a host site which references a marketed site. The method also can include identifying a link address for the link in the click through. The method yet further can include comparing the identified link address to a modified link address recorded for an actual link address for the marketed site. Finally, the method can include quashing the click through if the identified link address is not the modified link address. Conversely, the method can include redirecting the click through to the marketed site if the identified link address is the modified link address.