I made about $20 for 190,000 ad impressions. So I picked up about 10c CPM for adbrite. My beef with them is the spammy ads and apparently the RON ads I have been getting that I can't turn off without emailing them that now has pictures of the inside of people's guts (weight loss) and another one that is for a "queer and asian" community that really has nothing to do with my site.
That's always been in burstmedia's terms. It is a clause that protects them based on the contract you sign up with them for. So if you signup with them for a 3 year contract and get terminated in a few months, you owe them the difference of royalties earned for that extra 10% they gave you between the month to month and 3 year.