Online measurement company ComScore today released findings from its April 2009 “Video Metrix” data. Internet users viewed 16.8 billion online videos during that month, representing an increase of 16 percent versus March. A significant increase in video viewing at YouTube contributed to the month’s gains.

In April, Google Sites, whose online video properties include YouTube, once again ranked as the top U.S. video property with 6.8 billion videos viewed (equating to 40.7 percent online video market share), a 15-percent increase versus March. YouTube.com accounted for more than 99 percent of all videos viewed at Google Sites.

Fox Interactive Media, parent of social networking site MySpace, ranked a rather distant second with 513 million videos viewed, or 3.1 percent online video market share. Hulu.com followed in third place with 397 million videos viewed (2.4 percent market share), ahead of next-ranked Yahoo! Sites, with 355 million videos viewed (2.1 percent).

ComScore also reported that, across all the online video sites being tracked, nearly 152 million U.S. Internet users watched an average of 111 videos per viewer in April. Google Sites (again, the parent of YouTube), reached an all-time high of 107.9 million video viewers during the month. Fox Interactive Media (owner of MySpace) ranked second with 58.8 million viewers, followed by Yahoo! Sites (45.4 million) and Hulu (40.1 million).

Other notable findings from ComScore’s April 2009 report include:

• 78.6 percent of the total U.S. Internet audience viewed online video.
• The average online video viewer watched 385 minutes of video, or 6.4 hours.
• 107.1 million viewers watched 6.8 billion videos on YouTube.com (that averages out to 63.5 videos per viewer).
• 49 million viewers watched 387 million videos on MySpace.com (7.9 videos per viewer).
• Hulu accounted for only 2.4 percent of videos viewed, but made up 4.2 percent of all minutes spent watching online video.
• The duration of the average online video was 3.5 minutes.