ember - 5:06 pm on Aug 23, 2010 (gmt 0)
Nothing comes close to AdSense, which is one reason they keep competitors at bay, but direct advertisers do add extra revenue, moreso than Adbrite or Kontera or any of those. A lot of advertisers do not want to deal with Adwords or use Adwords and want another route as well. And if you can develop a good relationship with them, they'll stick around and are a good back up if AdSense tanks. Worth the effort.