With search absorbing half of US digital advertising spend, it is the most crucial channel for marketers to get right. Although it is maturing, it remains dynamic as marketers seek to serve search ads to users in more places and in new ways. To help guide marketers, our forecast includes an analysis of search users, volume, and spend, all broken out by device, as well as spend by industry vertical. New to the forecast are voice search user estimates and a segmentation of search ad spend by search engine, including eCommerce channels Amazon and eBay.