OpenAds founder Scott Switzer explains the basic about OpenAds Ad Server to Matt Asay of CNET – Let’s say I graduate from university and start writing a blog. At first, my mom and grandma read my site (begrudgingly, no doubt). At this point, Google AdWords is enough to make a few pennies. Once I get serious readership and want to monetize that, however, the next phase would be to use an ad server like Openads to tie into more sophisticated ad networks (using a more sophisticated ad server).
I could still use Google AdWords with Openads. It’s just another ad network, after all. But Openads’ software would give me more control over the ads served up on my site. It also allows me to deploy several different ad networks at once, letting me try out various ones to determine which is most effective for my audience. I could run them in rotation and designate the percentage that these ad networks serve ads to my site (based on contract, for example). I could have maximum control of the ads on my site. Link.