ClickBank is described as 'is the Internet's leading retailer of digital products. Whether you're looking to sell, promote, or shop for digital goods, ClickBank is for you'. There are more than 10 alternatives to ClickBank, not only websites but also apps for a variety of platforms, including Mac, Windows, iPhone and iPad. The best alternative is Avangate. It's not free, so if you're looking for a free alternative, you could try Bytemart.org or Commission Junction. Other great sites and apps similar to ClickBank are ShareASale (Paid), Blink (Paid), PayKickstart (Paid) and Affiliatly (Paid).
With the iTunes affiliate program you can link to media on the iTunes Store, the iOS App Store, the Mac App Store and the iBook Store and earn commissions from purchases made via those links, but creating affiliate links can be time-consuming and fiddly.
AffiliateWP is a robust and feature-packed affiliate tracking software for WordPress. Reliable Affiliate Tracking AffiliateWP tracks affiliate referrals reliably, even on servers with aggressive caching.