It doesn't get much more straight forward than this...

"Fully 62% of adult internet users have watched online video on a video-sharing website, a   figure that has nearly doubled from 33% in 2006, according to a research report (pdf) from   the Pew Research Center’s Internet & American Life project, which also found that 19% of   online adults use video-sharing sites on a typical day (compared with 8% in 2006)."

This article references the Pew Internet & American Life Project that I mentioned in a post   here.

Read the article on Seeking Alpha by clicking here.