Facebook became the second-largest online video viewing platform in the United States in August, leap-frogging Yahoo! but still trailing far behind YouTube, digital tracking firm comScore said.
ComScore said a total of 178 million US Internet users watched online video in August for an average of 14.3 hours per viewer.
Google sites, primarily YouTube, attracted 146.3 million unique viewers in the United States in August, Facebook 58.6 million unique viewers and Yahoo! 53.9 million unique viewers, comScore said.
Google sites saw 1.9 billion video viewing sessions in August followed by Facebook's 243 million and Yahoo!'s 229 million, it said.
The number of videos viewed at Facebook has been climbing steadily. In July, Facebook attracted 46.6 million unique viewers and Yahoo! 55 million.
Facebook viewers watched around 20 minutes of video on the social network in August, comScore said, while Google sites served up 4.5 hours of video per visitor.
Explore further: YouTube topped 100 million US viewer mark in January: comScore