Minimum CPMs, CPM Floors, Floating Defaults and How They Can Make You More Money
The way that an advertising network generally works is that they serve as many paying ads as they possibly can and then they will serve what is called a default. The default is an image or advertisement (often times this is code for another ad network) that you specify for them to serve in the event that they run out of paying ads. This is extremely likely to happen – hence why it’s a good idea to align yourself with multiple quality ad networks.
The practice of placing ad networks one after another in this chain of defaults is sometimes called “daisy chaining.” While it may not be the best you can do, it is still far better than working with only one ad network and only generating revenue from the ads that they can sell because you are further maximizing your CPM (or cost per one thousand impressions).
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