Ad impression numbers are about to go down—that is, at least, if RealVu has anything to do with it. The Salt Lake City-based ad tech startup has, with the blessing of IAB and accreditation from the Media Rating Council, developed technology that measures exactly when an ad has been really, truly actually viewed. Traditionally ad impressions have been tallied from the publisher side, meaning that all instances in which an ad had merely been called up were counted, even if the ad never even loaded. But RealVu is taking reporting to the client side, along the lines of the “viewable impression” rule that IAB introduced last month as a pillar of its guiding principles for digital measurement. “We feel like we invented the viewable impression,” says Troy Tribe, president and COO of RealVu.