Publishers still bristle at GroupM’s tougher viewability standards

GroupM’s strict definition of viewability is a touchy subject for publishers. It is so strict, in fact, that of the six publishers Digiday spoke to for this story, not a single executive was willing to go on the record. “It’s upfront season, man,” one said. Controlling roughly a third of global ad spend, GroupM holds a lot of sway.Read the full article