A total of 6.5 million Americans - many of them younger males who watch amateur and music videos - tuned into mobile video in August, according to data released by comScore.
On-demand video is the most popular format, with 3.6 million viewers, the study found. Amateur videos, such as those on YouTube, drew 1.3 million viewers, and represent the most popular type of content, followed by music videos and comedy videos.
