Given that you can buy solid inventory at a fraction of the cost, why wouldn’t you use ad networks almost exclusively, especially for test campaigns when you’re trying to optimize creative and call to action?

But ultimately, this whole model is unsustainable. Sites cannot continue to sell an increasing share of their ads at a couple bucks per thousand, and the increasing competition is going to cause ad network failures and consolidation SOON.

I just put up a blog post with more detail on how this is going to shake out.
\"Ad Networks Are a House of Cards – But a Great Deal\"
http://is.gd/Ste

Jason Baer
Convince & Convert – digital consulting for agencies
http://www.convinceandconvert.com/convince-convert-digital-marketing-blog