Even before the flurry of M&A activity currently taking place, the ad networks began to promote multiple targeting solutions and ad sales packages to media buyers. The networks began to move all of those models under one roof, offering buyers the ability to buy multiple solutions in one place, hoping to exploit the long tail of available inventory.

Before long, networks like Blue Lithium became generalists. The single model -- such as Tacoda's -- became increasingly rare. Essentially, the business models used to differentiate the networks from each other disappeared, resulting in the commoditization of network service offerings.

At the same time, major media companies that were often the sources of network inventory began adding their own network-like capabilities. Sites like AOL and Yahoo, which had previously allocated large swaths of inventory to the networks, began to offer themselves packaged as a network offering, such as AOL's performance network. All of a sudden, there was no way for ad networks to differentiate themselves from each other anymore, except on the basis of cost. And the situation became even more confusing for buyers, who were no longer able to distinguish between the various network offerings.