With cost per thousand ads a flat fee is paid for every thousand times a banner is shown to visitors. When a banner is shown on your site it is called an impression by affiliate companies.

These are commonly referred to as CPM ads. This can be confusing to new affiliates as the acronym implies that it is "cost per million" when it actually stands for "cost per thousand".

This advertising can be very lucrative for sites that get good traffic. For example, if an ad pays out a rate of $1.25 CPM and you had 10 thousand impressions today, you make $12.50.  That is $12.50 for that one ad spot. Keep in mind that you can have multiple CPM ads on each page. It can really start to add up!