YouTube is emerging as a major platform for news, according to a new study.
The Pew Research Center's Project for Excellence in Journalism has released an examination of 15 months of the most popular news videos on the Google Inc-owned site.
It found that while viewership for TV news still easily outpaced YouTube, the video-sharing site was a growing environment where professional journalism mingled with citizen content.
"There's a new form of video journalism on this platform," said Amy Mitchell, deputy director of the Pew Research Center's Project for Excellence in Journalism. "It's a form in which the relationship between news organisations and citizens is more dynamic and more multiverse than we've seen in most other platforms before."
More than a third of the most-watched videos came from citizens. More than half came from news organisations, but footage in those videos sometimes incorporated footage shot by YouTube users.
The Japanese earthquake and tsunami was the most-viewed news event during the length of the study, which spanned January 2011 to March 2012. The top videos from Japan included footage from surveillance cameras, a news network and a Japanese Coast Guard vessel - a typical variety of sources.
Such dramatic events were often among the most watched videos. Other popular news events included the Russian elections, unrest in the Middle East, the collapse of a fair stage in Indiana and the crash of an Italian cruise ship.
"One of the things that emerges here is the power of bearing witness as a part of a news consumption process," Ms Mitchell said. "Many of the most viewed stories that we're looking at here have real powerful imagery around them."