The MRC has lifted its advisory on viewable impressions, encouraging the industry to transact based on the metric. A recent blog from the IAB has also officially announced the standard for viewable impressions – 50% of pixels in view for at least 1 sec. While it still does not guarantee ad exposure, it does revalue inventory below the fold and makes us consider new proxies for attention. Viewability has been around for quite some time, but the lack of standards would lead to quite a bit of chaos when it came to transacting with the data. The IAB anticipates viewable video to come by this summer but viewability is just the start. I’d imagine we can expect viewability to be calculated based on total time and perhaps priced on a sliding scale in the future.