Facebook declined to comment on the record, but two of the companies in question – Kenshoo and Optimal – offered statements confirming this state of affairs.
Kenshoo says its Facebook Exchange solution is currently in "Early Access" mode, meaning it has not reached what Facebook calls the “General Availability” stage when it is added to the PMD directory and the new business starts flowing in.
A Kenshoo rep tells AdExchanger, "In the interim, Kenshoo is working within the Facebook Exchange ecosystem and partnering with direct service providers to fulfill customer demand while adding additional value through attribution and optimization across regular Facebook activity as well as other media channels such as search."
Optimal also says it's in the thick of the evaluation process, and preparing for a demonstration of its technology to the Facebook team. [x+1], the only major Demand Side Platform company still awaiting approval, didn't reply to an inquiry by press time. (update: [x+1] says it too is awaiting final approval.)