Since late 2007, the percentage of female Internet users ages 12 and older who have streamed a video online in the past 30 days has grown from 45% to 55%, an all-time high for this demographic, says the report, and nearly equal to the 59% of men who have recently streamed video content online.

At the same time, the percentage of adults aged 55 and older who have recently streamed video online has also increased significantly since December 2007, rising from 32% to 46% in that time span. Due to recent growth among women and older adults, online video streaming has become a mainstream activity and should be addressed as a mass market media, opines the report.

Despite some encroachment on traditional television viewing, the living room remains a preferred destination for video viewing due to emerging technologies such as HDTV, DVR, and Blu-ray. Among those adults who actively stream and download video content:

• 20% of the video content they consume is viewed on a PC. However, the PC is beginning to encroach on the time spent watching TV
• The share of video watching on the PC has almost doubled since early 2007 (from 11% to 20%)
• 67% of their video content is consumed on a television entranced by the increasing variety of content options and time shift control
• Short-form videos (amateur content, news, commentary, etc.) have benefited the most from online streaming
• TV show streaming has doubled in the past year, due in part to the networks allowing free streaming of their shows.

Among the various types of video streams offered online, shorter video clips, are by far the most preferred type of video file accessed today by Internet users. The popularity of short video clips has more than likely been driven by the universal appeal of YouTube, as 49% of those that have streamed or downloaded video content have accessed the site in the past 30 days.

Americans have embraced streaming video, often at the expense of video downloading. Data from the study confirms that nearly six in ten U.S. Internet users 12 years of age and older have streamed video in the previous 30 days. In comparison, almost one in five have downloaded video in the previous 30 days.

At least three in four digital video consumers say they would find it "very" or "somewhat reasonable" for advertising to be included in the free digital distribution of full-length TV shows and movies, while around two-thirds say the inclusion of advertising would be reasonable with free access to music videos, short news or sports clips, as well as movie/ TV trailers or previews. Fewer are ready to accept this "price of admission" for shorter-form content or less-professionally polished content.

The one content type that may be the exception to ad-supported willingness is amateur video content:

• 52% of consumers age 12+ who have downloaded or streamed video say they would find it "not very" or "not at all reasonable" to have advertising embedded within free amateur or homemade videos online
• Some video sharing websites are beginning to diversify their content offerings to include longer, professionally produced material that may be advertising-supported. The current audience has grown accustomed to free streams without advertising

2009 data from the comScore Video Metrix service shows that U.S. Internet users viewed 14.8 billion online videos during the month, representing an increase of 4 percent versus December 2008. YouTube accounted for 91% of the incremental gain in the number of videos viewed versus December, as it surpassed 100 million viewers for the first time.

 In January, Google Sites ranked as the top U.S. video property with YouTube.com accounting for more than 99 percent of all videos viewed at the property. Fox Interactive Media ranked second, followed by Yahoo! Sites.

More than 147 million U.S. Internet users watched an average of 101 videos per viewer in January.

Other notable findings from comScore from January 2009 include:

• 76.8 percent of the total U.S. Internet audience viewed online video
• The average online video viewer watched 356 minutes of video (6 hours), up 15 percent versus December
• 100.9 million viewers watched 6.3 billion videos on YouTube.com (62.6 videos per viewer).
• 54.1 million viewers watched 473 million videos on MySpace.com (8.7 videos per viewer).
• The duration of the average online video was 3.5 minutes, up from 3.2 minutes per video in December.
• The duration of the average online video viewed at Megavideo was 24.9 minutes, higher than any other video property in the top ten

For more from Ipsos, please visit here, or here, or from comScore, please go here.