I am running a few AdBrite ads on a site just to see how it performs, and I'm sad to say it's doing very poorly! I get anywhere between 300-500 impressions a day on my ads and always earn either $0.01 or $0.02, almost never more even if I end up with an ad click! If I get a click in PubCenter or Google AdSense I am typically earning a whole lot more than that, so it's very surprising to see only a penny earned through AdBrite!
I never ever use adbrite. They don't know business, it doesn't matter if you are an advertiser or a publisher, either way you are just wasting your time and money. Bottom Line "Adsense".
Adbrite is mostly for sites that get banned from Adsense or who aren't allowed in Adsense... and its good for purchasing cheap CPM ads from stupid webmasters who use Adbrite!
They get away with the payments because they don't care about the publishers. That's why I stick with Google.