• by Mark Walsh  @markfwal, February 23, 2009

The appetite for video continued to grow in the fourth quarter as U.S. consumers watched more programming across television, the Internet and mobile devices than the prior quarter, according to Nielsen's latest A2/M2 Three Screen report.

Americans viewed a record average of 151 hours of TV monthly in the quarter, while those tuning into online video averaged nearly three hours, and mobile video users watched for almost four hours monthly.

Time-shifted television had the biggest gain, increasing to an average of seven hours and 11 minutes from 6:27 in the third quarter and from 5:24 a year ago--a 33% annual jump. For young people, watching video online and on a DVR are equally popular, with an average of five hours spent monthly on each format.

"The American fascination with television and other video content is not easing up, as consumers keep turning to TV, Internet and mobile at record levels," said Susan Whiting, vice chair of The Nielsen Co., in a statement. "Viewers appear to be choosing the best screen available for their video consumption, weighing a variety of factors, including convenience, quality and access."

Overall time spent online, however, was down slightly from the third quarter at 27:11 and up only a minute from a year ago. When it comes to online video, time spent increased quarterly from 2:31 to 2:53. Not surprisingly, viewership is highest among young consumers, and the workday remains the most popular time for tuning in. Some 65% of the Web video audience is watching from 9 a.m. to 5 p.m. Monday to Friday, compared to 51% between 6 a.m. and 8 p.m. on weekends.

The mobile video audience increased 9% between the third and fourth quarter to 11 million, while time spent rose 2% to 3:42. The nearly four-hour average underscores that people are willing to watch long-form content on mobile devices--a welcome sign for TV networks pushing more and more prime-time shows onto cell phones.

Nielsen, however, issued a report last month that showed that mobile video growth had hit a plateau, with only 5% of U.S. subscribers watching mobile TV and mobile video subscriptions up only 1% over last year to 7.3%.

The TV and Internet audience figures are calculated using Nielsen's National TV and Internet panels, while mobile phone data is collected through a quarterly survey.