Whether you are using ClickBank, or Commission Junction, a special affiliate code is assigned to you based on your account. Typical Affiliate codes look something like:
http://YourName.reseller.hop.clickbank.net/AffiliateName
or
http://paydotcom.net/?affiliate=1234567890'
Ugly, ugly, ugly. You also don’t want folks to bypass you (keeping you from collecting on commissions). To ensure that you are not robbed of commissions, and to maintain a beautiful look to your link, you should mask all of your affiliate codes. There are a couple of ways to do this. As a minimum, you should do #1 & #2 below, and for ultimate security, #3 is required.