Consumers now consider online video an integral part of their web browsing experience, and it has overtaken email in terms of unique audiences, according to a Nielsen Netratings report.
Time spent on video sites has grown nearly 2,000% since 2003. Over the same period, the number of US users frequenting online video sites grew 339%.
In the past year alone, unique viewers of online video grew 10%, placing the category second only to social networking sites by growth.
Interest in online video is split fairly evenly across demographics, Nielsen said. YouTube continues to dwarf all other video sites, but much of the growth since January has been among sites hosting long-form content, such as full episodes or sports matches.
But despite the growth in online video use, it does little to threaten television viewership, Nielsen CEO John Burbank said.
"We don\'t see cannibalization at all. People who watch a lot of web video also watch a lot of television," he said.
The popularity of social networking sites increased 11% over the past year, and 87% since 2003. Search continues to be the top web usage category, but its audience grew by just 4% last year. Email users grew by only 3% last year.