by: Tim Peterson and Charlie Warzel | AdWeek

Is the viewable impression going nowhere fast? A full two years after the Interactive Advertising Bureau, Association of National Advertisers and the 4A's launched Making Measurement Make Sense (3MS), a cross-industry effort to improve Web ad metrics, and a year after viewability took center stage at the IAB’s annual meeting, the movement seems to be running in place. Instead of rallying around a new ad currency, questions continue to arise over the most practical of issues, such as how to measure, implement and enforce viewable impressions—and whether the whole conversation is even worthwhile.