Unless you've been under a rock somewhere for the last five years, chances are that you might already know what cost-per-click advertising is. It is an innovation that was invented (or at the very least popularized) by the Google Corporation in the form of their Adword program. This program almost single-handedly resurrected the online marketing game and once again made it possible for people to earn gigantic incomes simply from maintaining a popular website. Of course, that particular angle of things is through the Adword compliment program; Google AdSense. If you are interested in cost-per-click advertising, then you are going to be buying ad space, not selling it.