An affiliate network acts as an intermediary between publishers (affiliates) and (merchant) affiliate programs. It allows publishers to find affiliate programs, which are suitable for their website and it helps websites offering affiliate programs reach its target audience.

In addition to the traditional affiliate networks exist also lead generaion and CPA networks. Lead generation networks are typically networks that next to performance based promotions (affiliate marketing) also offer CPM or CPC based display advertising. CPA networks on the other hand are often so-called "super affiliates" who are themselves affiliates of merchants via the traditional affiliate networks and recruit other affiliates to promote the merchant through them instead of directly via the merchants program at the traditional network.

CPA networks take advantage of the ability to get higher commission rates due to their high volume, which they pass in part down to their affiliates. Average affiliates get usually paid a lower commission if they promote the merchant directly, because they are rarely able to generate the required volume to reach the higher payout tiers.