"Yes, we do work with multiple DSPs, but the unifying thing is always the layer on top of it," Grether said. "It's crucial for us that we have the universal layer that synchronizes the pipes we use to access media."
Additionally, Grether says Xaxis snaps up more inventory directly from publishers than through exchange buying, and those buys use programmatic pipes based on Xaxis' own technology.
Grether's claim that DSPs have been commoditized represents a significant about-face from its position one year ago. Last fall, when Facebook launched its ad exchange, Xaxis was the only trading desk with a direct "seat" among the seven or so DSPs anointed to access that inventory. Direct access to FBX became part of Xaxis' marketing outreach and seemed to differentiate it from other trading desks -- especially VivaKi AOD, which was briefly locked out of FBX when it became clear that its preferred DSP, Google's Invite Media (now DoubleClick Bid Manager), would not be allowed to bid there. Cadreon, Accuen, and other agencies accessed FBX through Turn, MediaMath, and other preferred DSP relationships.
Today, the number of FBX marketing partners has ballooned to 17, and Xaxis is no longer one of them. Executives say Xaxis buys loads of FBX inventory, but through other DSPs rather than its own.
"At that time we were one of the few," says Grether, referring to the FBX beta period. "And therefore it was a strategic advantage. But now as there are 17 pipes, having one of the pipes is not a competitive advantage."
The move by Xaxis to embrace multiple DSPs is not unlike VivaKi AOD's recent diversification of its trading platforms. After several years of nearly-exclusive trading on DoubleClick Bid Manager, AOD has lately added more partners, including MediaMath and Turn for display advertising, GraphEffect and Voxsup for social, and Adelphic for mobile. In fact, it now serves more ads through Turn than through Google's DBM.
The difference between the two is that AOD was motivated, not by DSP commodification, but seemingly by the opposite -- differentiation. Go figure.
The changes at AOD and Xaxis may point to growing consensus that the proper role for agencies is systems integrator, Pivotal Research analyst Brian Wieser suggested.
"The role of the trading desk may be evolving such that uniformly it is about integrating technology and pairing it with humans who socialize ideas," he said. "That's ultimately what agencies do."
Xaxis is by most accounts the largest member of the trading desk family. Its 300 employees typically manage more than 1,000 brand campaigns concurrently. It has recently rolled out new integrations with radio and out-of-home inventory, and continues to iterate around methods to buy premium inventory programmatically.
Correction: An earlier version said Xaxis "said goodbye" to its in-house ad server. In fact, it merely diversified. 24/7 Real Media's Open AdStream (the in-house option at WPP) is still among the technologies it uses.