I was looking at Adbrite as a contextual ad service today and I noticed that when I highlighted two particular categories they gave impression numbers in the millions. 8.06m for business/finance 4.15m for health & wellness PER DAY. Needless to say I was shocked. Now I know just seeing an ad and actually clicking on it are two separate things. Furthermore the visitor actually has to click on your ppc ad to make any actual money. But lets do the calculations for a sec. Lets say for every visitor to your site about 1 in every 100 convert. Your topic was in health & wellness so your ad would show up 4.15m a day. Lets say about 1 out of every 1000 people who see your ad clicks on it so that's 4.15m/1000. So your talking about 4150 visitors a day. You would get 41 clicks every day. That's about 1245 a month. Does anyone see the problem with that number? Even if only 1 out of 1000 people who saw your ad clicked on it, even if only 1 out of every 100 people who came to your site clicked on an adsense ad, even if you only made $1.00 a click, you would $1000 a month. Has anyone had any kind of results like this in adbrite?
You also have to factor in the quality of AdBrite's network. They literally accept anyone to their network - sites with horrible horrible quality content / vistitors. Often times sites that have been banned from higher paying networks... More fraud, crappy visitors. You pay for what you get.
I used AdBrite for about 3 - 5 months. I got a good amount of leads, but they never converted into much money. Although some people think they are a great place. They just didn't seem to work out for me. I guess it just depends what your trying to push. My suggest though would be to try something like exoclick.com