Affiliate networks, such as ClickBank, are much more susceptible to hijacking than standalone programs. This is because of the greater statistical likelihood that any given referred prospect will already be a program member. Few prospects would go to the effort of joining a new affiliate program, merely to secure an illicit discount, but many would be tempted by easy savings from an existing program membership.

Before ClickBank introduced its current hoplink procedure, it was possible for a link thief to misappropriate the commission on a purchase, simply by re-invoking the hoplink process using a manually entered URL. The ease with which a dishonest affiliate could "type and steal" made it an attractive target for casual thieves.

But this loophole was eliminated as part of a range of security enhancements introduced by ClickBank in August 2002. And referral security was further tightened during the October 2003 upgrade to the hoplink system. Although these measures do not constitute perfect solutions to the ongoing problem of link theft, the progressive enhancement of the referral system is helping to deter the casual hijacker.

Merchants can also play a role in protecting their affiliates against referral losses, both through education and through the use of protective technologies.

A small minority of merchants employs the somewhat drastic step of screening every purchase and validating the referring affiliate (if any) prior to the delivery of the product. The validation occurs in real-time, using a database of registered affiliates. If the referral comes from a known affiliate, the product is delivered in the normal manner. But if the referrer is unknown - as would be the case when a link theft occurs - the buyer finds herself in the embarrassing position of explaining how the referral occurred. Unfortunately, the technical challenges in implementing and managing such a system with ClickBank are likely to exceed the benefits it would deliver.

If all else fails, the affiliate can take her own steps to protect and survive. The simplest of these involves only minor changes to the HTML code used in the web pages containing referral links and other techniques, including the ever-popular link cloaking, are in widespread usage.

But, despite the considerable selection of protective technologies employed by ClickBank, its merchants and their affiliates, none is foolproof. For example, a determined link fraudster can defeat every known defensive system simply by deleting her ClickBank cookie file prior to making a purchase. If an affiliate is sufficiently savvy and committed to gaining an undeserved commission, nothing will stand in her way. Therefore, as with any business problem, we must avoid the temptation to become obsessed with referral security at the expense of our other profit-making activities.

Copyright © Tim Coulter. All rights reserved.

Tim Coulter is a consultant and software developer who helps netpreneurs to harness marketing technologies.

He is also the author of "ClickBank - The Definitive Guide" The Ultimate ClickBank Tutorial & Reference Manual.

http://www.clickbankrevealed.com/