To start off, not all
link theft is intentional. Sometimes it is just the webmaster not knowing that the way he/she has set up his/her link directory will not provide search engine link benefit to anyone that links to them. Although, some link theft can be
very intentional. The webmaster knows exactly what he/she is doing.
Stealing of links can be easy to do, affiliates replace your affiliate link with theirs. And there goes your commission. By-passing of links can be easy to do also. When users discover the real domain name of the product, they will just go to the site directly, and again you will lose valuable commission.
By following the suggestions below you can make sure that you will not be the next victim of commission theft:
If a website asks you to exchange links, DO NOT link to them to them until they have given you the URL location of your link in their link directory. If you link to them first they may forget to add your link.
Also offer a enticing bonus/incentive on your site to all those who order thru your link, and then require them to supply their receipt in order to obtain the bonus. If you have a compelling incentive/bonus (such as a special report, membership, coaching, services, etc.) that you offer as a bonus when visitors order thru your affiliate link, you will remove the vast majority of the risk. (Because the only way to access your bonus is by the visitor using your affiliate link to order). The greater the bonus, the greater the decrease of commission theft.
In closing there is no reason to leave your business vulnerable to this kind of theft when you can easily protect your business. I'm not trying to worry you. It is, what it is. We've all seen the statistics that affiliates are losing anywhere from 10-40% of commissions because of affiliate link by-passing or stealing. This a real problem for affiliate marketers. That is why I cloak all my affiliate links! If you feel you are not getting the sales you incur, you should really look into investing in a high grade affiliate link cloaker.
All the Best To You,