List of Top 25 Online Advertising Network

1. Platform-A ( Advertising.com )
2. Yahoo! Network
3. Google Ad Network
4. ValueClick Networks
5. Specific Media
6. FOX Audience Network
7. 24/7 Real Media
8. Traffic Marketplace
9. Microsoft Media Network US
10. Tribal Fusion
11. Casale Media – MediaNet
12. interCLICK
13. Turn, Inc
14. Adconion Media Group
15. CPX Interactive
16. Collective Network by Collective Media
17. ADSDAQ by ContextWeb
18. AudienceScience (formerly RevenueScience)
19. Burst Media
20. Undertone Networks
21. AdBrite
22. Pulse 360
23. Vibrant Media
24. Adify
25. Kontera

Source: April 2009 comScore Media Metrix