MediaPost has the details from SpotXchange CEO Mike Shehan who says about 20% of their ad spend is now on mobile, compared to 4% last year. Shehan says, perhaps most surprising, was the rise of private marketplaces for programmatic buying and selling. More than 40% of the impressions managed on their platform happen through private marketplaces, a 112% increase year-over-year from 2014. Shehan says he thinks this growth may signal "the tipping point we've been waiting for" in programmatic.
