NEW YORK (AdAge.com) -- No other subject has become as much of a hot button in the ad industry as procurement. Marketers' ROI mania and growing use of procurement officers to purchase marketing services has pushed down agencies' operating margins. But has it gone too far? Speaking at the ANA Annual Conference in Phoenix, Ad Age editor Jonah Bloom questions whether the process has lost a sense of balance and is ignoring the crucial need of agencies to invest in the services, technology and talent required to promote brands in this fragmented age.