An affiliate network acts as a go-between between publishers and merchant affiliate programs.  They allow website publishers the ability to find and partake in affiliate programs suitable for their website.  In turn they generate income from these affiliate programs, this in turn allows websites offering affiliate programs to reach a greater audience.   As the Affiliates grow their network by adding more website publishers they continually gain more leads, sales and revenue.

Traditional affiliate networks permit merchants to tender publishers a share of revenue generated by the merchant from visitors to the publisher's site, or a payment for each visitor on the publisher's site that completes a specific action.  For example they may make a purchase, register for a newsletter, download a whitepaper, or fill out a questionnaire.  

For merchants, affiliate network services and benefits may comprise of tracking technology, reporting tools, payment processing, and access to more publishers. For affiliates, services and benefits most generally include simplifying the process of registering for one or more merchant affiliate programs, reporting tools, and payment aggregation.

Affiliates are typically able to enroll in affiliate networks for free, whereas there is usually a fee for merchants to join. Traditional affiliate networks typically charge an initial setup fee and a recurring membership fee. In addition it is quite common for affiliate networks to charge merchants a percentage of the commissions paid to affiliates.