Ad CategoryThe different types of ads offered by an affiliate program. The most typical ad. categories are listed below:
CPM - cost-per-thousand impressions. This may sound like how much advertisers pay for 1000 of their ad impressions, but it actually means how much you get for ads to appear on your website 1000 times. In other words, the CPM pricing is your pay rate per 1000 impressions of the ad (i.e. banners, popups, etc)
CPC - cost-per-click. This is how much you will be paid PER CLICK of the ad. Depending on how much your visitors like to click on ads, your earnings will vary. Most people OVER-estimate the click - through rates of their visitors. Imagine you have a website that has roughly 10000 page views each day, the number of ad clicks you will get is typically 0.1% to 0.5% of the total number of page views. Hence, by calculating the numbers, you will get about 10 to 50 clicks. Now, if you're paid the average market rate per click, that is......10 cents per click, you will earn about 1 dollar to 5 dollars in a day. This logic may sound simple, but lots of inexperienced webmasters set much higher estimates for this click through rate, so be sure you analyze your traffic and visitors well before you're ready to make some sort of estimation for your earnings.
CPA -cost-per-action. Advertisers pay to display their banners on your website, and they pay to have people click on their ads but in the end, their real goal is to get these visitors to do something, whether it be to buy their product, to buy their service or to sign up for their program. These CPA programs achieves just that. According to the different action specified, you will be paid only when your visitor(s) perform that action. For example, suppose, the action specified is for a visitor to sign up for the company's newsletter, then you will get paid only when the visitor sign up. In general, the CPA pay rates are significantly higher than the CPC and CPM rates, since it's more to difficult to get your visitors to do something in addition to viewing and clicking the ads.
CPL - cost-per-lead. This type of ad pays you when your website successfully leads the visitor to the advertiser's web page. Let's say you recommend your visitors to use a certain web host, and provides them with a link to the web host's website. Once, the visitors goes to that host from your page, then you have accomplished one successfully lead.
The above descriptions are the general definitions applied to these ad categories. Be sure to double check the specific program's own definitions for CPM/CPC/CPA/CPL, occasionally, the program changes the category's definitions slightly to suit the specific program needs. | 
