Affiliates were among the earliest adopters of pay per click advertising when the first pay-per-click search engines emerged during the end of the 1990s. Later in 2000 Google launched its pay per click service, Google AdWords, which is responsible for the widespread use and acceptance of pay per click as an advertising channel. An increasing number of merchants engaged in pay per click advertising, either directly or via a search marketing agency, and realized that this space was already occupied by their affiliates. Although this situation alone created advertising channel conflicts and debates between advertisers and affiliates, the largest issue concerned affiliates bidding on advertisers names, brands, and trademarks. Several advertisers began to adjust their affiliate program terms to prohibit their affiliates from bidding on those type of keywords. Some advertisers, however, did and still do embrace this behavior, going so far as to allow, or even encourage, affiliates to bid on any term, including the advertiser's trademarks.
Commission Junction — This site serves as a clearinghouse for thousands of companies and small businesses looking to get into the affiliate business. It offers myriad affiliate programs, but you must apply separately to each one. Payout rates vary wildly, up to 50 percent, and some commissions are based on leads or clicks vs. sales. Frustratingly, Commission Junction deducts $10 from your accrued earnings for every month in which you don’t actively earn commissions; if you let your account lapse, your income could get wiped out.
Pay-Per-Click is also considered as widespread and common affiliate agreement. Under this agreement, the affiliate marketers will get fixed rates depending on the number of clients who click on the links placed on the affiliate website that leads to the merchant website. Here a purchase is not necessary to earn commissions, all that has to be done is that the client clicks the link and stays at least thirty seconds on the merchant website. Regardless of what the visitor does on the merchant site, this will not affect the commission.
This is the most popular payment offered by most of the affiliate programs. Under this program, the affiliate marketers earn commissions from the merchant each time they will send a client to the merchant website, and that client makes an actual purchase. Various affiliate programs offer a specific percentage of the sale as commission while others will pay you a fixed rate for every sale.
While these models have diminished in mature e-commerce and online advertising markets they are still prevalent in some more nascent industries. China is one example where Affiliate Marketing does not overtly resemble the same model in the West. With many affiliates being paid a flat "Cost Per Day" with some networks offering Cost Per Click or CPM.
In February 2000, Amazon announced that it had been granted a patent on components of an affiliate program. The patent application was submitted in June 1997, which predates most affiliate programs, but not PC Flowers & Gifts.com (October 1994), AutoWeb.com (October 1995), Kbkids.com/BrainPlay.com (January 1996), EPage (April 1996), and several others.