Myth #5: Brand advertisers should be on the ad networks.
Reality: Not all brand advertisers are created equally. While there will be brand advertisers who should use ad networks to achieve scale and optimize their frequency distribution, there will always be brands that will eschew the networks. Issues of control and transparency will continue to affect ad networks. Any advertiser uncomfortable with the lack of control inherent in ad networks will either need to adjust their expectations or avoid the networks altogether. The more image and brand conscious an advertiser is, the further it will be from the ad networks.

Myth #6: Ad networks are a bargain.
Reality: Certainly there are still bargains to be found in ad networks. However, the acquisition activity within the industry, combined with increasing analytical sophistication, means ad networks are becoming more expensive. While inventory is still sold on a CPC or CPA basis, ad networks are calculating the eCPM and a buy will automatically be bumped from prime inventory by an advertiser that is willing to pay more, or whose advertising is more effective. Even if a rival CPC is lower, the network can conceivably earn more revenue if the CTR is higher. Sound familiar? The dynamic in ad networks is beginning to replicate trends in search engine marketing.

Marissa Gluck is co-founder and managing partner at Radar Research.