Notice: Smowtion does not exist anymore.
Smowtion is a site just like Google Adsense. You need to have a website of any kind, like a site, or a blog. Register and add your sites. Then choose which kind of banner you would like to put on your site. Then start earning from it. You would earn for clicks made through the ads.
The available ads are all in image format. You can put the ads even if your site is a file-sharing, video-sharing or adult website.
So, if your site have issues with other ad network sites, you can try Smowtion.