I came across this list the other day of Advertising networks.
HUGE List.. thought I would share.. I honestly haven't heard of most of them..

CPA is Cost Per Acquisition;
CPC is Cost Per Click;
CPM is Cost Per 1000 Ads Displayed (where M is the Roman letter for 1000)

Adsense from Google

1. Google Adsense : Grand-daddy of contextual advertising. (CPC)

Adsense Alternatives

1. Chitika : Shopping mall banner advertising. (CPC)
2. AdBrite : Ad marketplace for publishers and advertisers. (CPC); 75% payout.
3. Advertising.com : Large network. (CPA)
4. 24/7 RealMedia : Large network. (CPM)
   
5. Burst Media : Large network. (CPM)
6. Commission Junction : Large network. (CPA)
7. Kanoodle : Large network. (CPC); 50% payout.
8. LinkShare : Large network. (CPA)
9. ValueClick : Large network. (CPM)

Two Big Ones Coming Soon

1. Yahoo Publisher Network : Closed Beta (CPC)
2. MSN adCenter : Closed Beta (CPC)

A few more Advertising Networks

• Accelerator Media :
• AdAgency 1 : (CPM) ; 60% payout.
  
• AdDynamix : (CPM)
• AdEngage :
• Adgenta :
• Adhearus :
• AdKnowledge : (CPC)
• AdPepper : (CPM)
  
• ADServing Network : (CPM)
• Adsmart : (CPM)
• Adtegrity : (CPM)
• AdZuba : (CPM)
• AffiliateFuture : (CPA)
• AffiliateSensor :
  
• AllFeeds : (CPC); 60% payout.
• AVNads :
• AzoogleAds : (CPA)
• Banner Boxes : (CPC)
• BannerConnect : (CPM)
• BardzoMedia : (CPM)
  
• BidClix : (CPC)
• BidVertiser : (CPC)
• BlinkAds : (CPA)
• BlueFN : (CPA)
• BlueLithium : (CPM)
• Casale Media : (CPM); 70% payout.
  
• ClickAdsDirect :
• ClickBooth : (CPA)
• ClickShare :
• Clicksor : (CPC); upto 85% payout.
• ClickXchange : (CPA)
• ContexWeb : (CPC); 50% payout.
  
• CoverClicks :
• CPX Interactive/Budsinc : (CPM)
• DirectNetworks : (CPA)
• Enhance Interactive :
• Esource Media : (CPM)
• Etype-Europe : (CPM)
  
• EtypeUSA :
• ExpoActive :
• FastClick=ValueClick : (CPM); upto 65% payout.
• FluxAds : (CPA)
• HurricaneDigitalMedia : (CPM); 60/75% payout.
• Hyperbidder : (CPC)
  
• IncentaClick : (CPA)
• Industry Brains :
• Interclick :
• JoeTec : (CPM)
• Kontera : (CPC)
• Mamma Media Solutions : (CPC); 50% payout.
  
• MaxBounty : (CPA)
• Mirago :
• MIVA AdRevenue Xpress :
• Nixxie :
• Oridian : (CPA)
• Oxado : (CPC)
  
• Paypopup : (CPM)
• PeakClick :
• Popup Traffic : (CPM)
• Quigo : (CPC)
• RealCastMedia : (CPM)
• RealTech Network : (CPM)
  
• Revenue Pilot : (CPC); 60% payout.
• RightMedia : (CPM)
• Searchfeed : (CPC)
• ShareAShare : (CPA)
• TargetPoint : (CPC); at least 50% payout.
• TextLinkAds : (CPC)
  
• TMP Express : (CPA)
• Tremor Network :
• Tribal Fusion : (CPM)
• Veoda : (CPC) ; 60-90% payout.
• Vibrant Media IntelliTXT : (CPM)

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