The shift from desktop to mobile, whether smartphone or tablet, is happening across a variety of activities, including social networking and digital video viewing. And tablets are key to the trend. As social networking and video reach plateaus in terms of share of total desktop time (around 29% and 18%, respectively), these activities are growing more quickly on smartphones, and especially tablets. The share of all tablet time spent with video, for example, will nearly double this year, from 10% to 19%. Read the rest at eMarketer.