Cost per mille requires only that the publisher make the advertising available on his or her website and display it to the page visitors in order to receive a commission. Pay per click requires one additional step in the conversion process to generate revenue for the publisher: A visitor must not only be made aware of the advertisement but must also click on the advertisement to visit the advertiser's website.
Two-tier programs exist in the minority of affiliate programs; most are simply one-tier. Referral programs beyond two-tier resemble multi-level marketing (MLM) or network marketing but are different: Multi-level marketing (MLM) or network marketing associations tend to have more complex commission requirements/qualifications than standard affiliate programs.
Forms of new media have also diversified how companies, brands, and ad networks serve ads to visitors. For instance, YouTube allows video-makers to embed advertisements through Google's affiliate network. New developments have made it more difficult for unscrupulous affiliates to make money. Emerging black sheep are detected and made known to the affiliate marketing community with much greater speed and efficiency.
The problem with affiliate marketing, like many other home business options, are the so-called gurus and get-rich-quick programs that suggest affiliate marketing can be done fast and with little effort. Odds are you've read claims of affiliate marketing programs that say you can make hundreds of thousands of dollars a month doing almost nothing ("Three clicks to rich!"). Or, they suggest you can set up your affiliate site, and then forget it, except to check your bank deposits.