“Having gone from zero to mass market globally in three short years, online video is the fastest-growing media platform in history, according to a new report from social media research consultancy Trendstream and research firm Lightspeed. In one week in January, 97 million Americans viewed a streaming clip online — as many as are tuning into any major broadcast network — according to a recent survey of 1,000 U.S. active Web users ages 16-65.