Forum Moderators: skibum
If you are looking for banner-broker type agencies, you might want to check out fastclick.com or valueclick.com.
CPM rates are far less than stellar right now, and you may be better off using one or more of the affiliate networks such as cj.com, onresponse.com, directleads.com, or websponsors.com. It takes more time and effort to manage your ads, but can be fruitful. Some of these companies have banner rotators, so you just pick the ads you want on their console, and just use 1 (or more) add codes on your site.
Using affiliate programs gives you the control over the ads you show, and allows you to tailor the ads to fit your demographic and site topic. This means you may be able to (sometimes tremendously) outperform the typical banner broker type deals. It does take more on your part to manage and evaluate the ads/merchants.