Ad agencies like to be able to optimize their own campaigns and that's why ad exchanges can be a better bet than ad networks, said Dave Marsey, Senior VP and Group Media Director at Digitas, during the Beet.TV online video leadership summit in New York last month.

"With an ad exchange you can buy the attributes of your audience…it can outperform because you are being more particular about the audience and layering in impressions," he said during a discussion on ad networks and ad exchanges.

But exchanges work best for direct response needs and acquisition, whereas ad networks still play a vital role in helping an advertiser achieve reach and frequency in a short period of time.

The ad networks that thrive will be the ones that invest in smarter technology and help marketers with ad formats, added James Kiernan, Senior VP and Managing Director at Zenith Optimedia, in this segment.

Daisy Whitney

Disclosure:  This event was sponsored by Tremor Video and hosted by Digitas.