You are going to need this if you want to make ad revenue from your WordPress blog. What WordAds essentially does is: Gather good ad deals with various businesses and then offer those businesses ad-space on WordPress blogs in exchange for revenue, some of which will go to the blogger. As standard you don’t make any money of the ads on your blog. If you get premium you can choose to remove ads all together. Or alternatively, you can set up WordAds and allow them to continue showing ads on your page in exchange for a reasonable cut of the revenue. In order to qualify for this however you must have your own domain name. Meaning: a URL without the “.wordpress” part. But rest assured, you can get this for free if you upgrade to the premium WordPress plan. Alternatively you can buy your domain from another service, like for instance GoDaddy.com. This might be cheaper than a premium plan but the premium plan comes with other benefits besides domains and WordAds. Such as greater control of your WordPress. The ability to use plugins, so on so forth. What fits you best is all up to you. Here are the tools. Now go out, and build an empire.
Source: Apply for WordAds — WordAds