For more insights and stats about how consumers use social media, please see Nielsen’s Q3 2011 Social Media Report

For more smartphone market data and insights about how consumer use their mobile devices, please see Nielsen’s Mobile Media Report for 2011.

Even though fewer people in the U.S. viewed video online during the month, users spent more total time watching – four and a half hours on average during the month, an increase of 4 percent from May.

Among the top online video destinations, only The CollegeHumor Network seems to have avoided the effects of summer as the number of unique U.S. video viewers increased 23 percent from the prior month.

Dailymotion showed the strongest month-over-month growth among the top 10 destinations for video streaming, up 21 percent to 183 million videos.  VEVO also saw an increase in video streams from May (+3%), while top online video destination YouTube held steady with 8.9 billion videos streamed during June.

U.S. video viewers spent more time on average watching video on Netflix than on any other site – 8 hours, 34 minutes, which is more than twice the amount of time spent watching content on Hulu, the #2 site by time per viewer in June.

New to the top 10 destinations by time spent per viewer, CBS Sports saw the largest increase in the average amount of time U.S. viewers spent viewing video on the site, up 87 percent from May.

Note: Due to data collection issues resulting from changes in the format of Netflix stream URLs, all metrics for the Netflix brand were excluded from the April and May 2011 online video rankings. As a result, there is no month-over-month change for Netflix metrics during June 2011.

Among the top online video destinations, MSN/WindowsLive/Bing saw the largest month-over-month growth in unique viewers (+29%), followed by Fox Interactive Media (+21%), Hulu (+18%) and AOL Media Network (+14%).

Double-digit growth in unique viewers also brought double-digit gains in streams for MSN/WindowsLive/Bing, AOL Media Network and Hulu.  CBS Entertainment Websites also saw a notable increase in streaming activity during May, up 13 percent from April to 120.7 million streams.

On average, U.S. viewers spent the most time watching Hulu content during the month of May, spending 4 hours, 43 minutes viewing Hulu videos across the Web.  Hulu was followed by Ustream.tv and Justin.tv – both of which streamed replays of the April 29 Royal Wedding causing average time spent viewing video on these sites to increase by 61 percent and 55 percent, respectively.

As the traditional television season wrapped up, viewers also increased their time spent watching video content on network-related destinations ABC Family (+28%), Lifetime Digital (+12%), Cwtv.com (+12%), and MTV Networks Entertainment & Games (+7%).

Note: Due to data collection issues resulting from changes in the format of Netflix stream URLs, all metrics for the Netflix brand will be excluded from the May, 2011 online video rankings.

While overall web activity decreased slightly in April, YouTube increased U.S. visitors over the prior month, with average visitors spending 2.9 percent more time on the website in April. Visitors to AOL’s network of sites also spent more time on average, about 5 percent longer during April.

While 194.8 million Americans went online in April, overall Internet use is down 2.4 percent from March. Not surprisingly, with the shorter month U.S. consumers spent slightly less time online on average (-3.8%) in April, and visited fewer unique sites compared to the month prior. Despite the slight monthly decline in time spent, Nielsen estimates that Internet access at home and work grew to 244 million individuals in the U.S. during April 2011.

The top 10 video sites in April are largely the same as last month, with only a slight change among the ranks. AOL Media Network and The CollegeHumor Network saw the largest month-over-month increase in unique viewers – up 13 percent and 11 percent, respectively – placing them just ahead of Hulu, which was the #6 video brand in March.

YouTube’s usage was at an all-time high in April as their U.S. viewers consumed 8.7 billion streams, up 7 percent from last month.

New to the list of most heavily used sites with double-digit gains in streams from March were Dailymotion (+61%), AOL Media Network (+31%) and Megavideo (+25%).

Three of the top 10 most engaging video brands in April saw their video viewers more than triple their average time spent viewing video on the site. Time spent viewing video on The Church of Jesus Christ of the Latter-Day Saints was up 254 percent, due to Easter-related content. Ustream.tv and CBS Sports also saw significant growth as viewers increased their video viewing time by 246 percent and 239 percent, respectively.

Note: Due to data collection issues resulting from changes in the format of Netflix stream URLs, all metrics for the Netflix brand will be excluded in the April, 2011 and May, 2011 online video rankings.

For the second month in a row, VEVO is the #2 video brand in the U.S.  With 33.3 million unique video viewers, VEVO has 4 percent more video viewers than #3 Facebook, but trails consistent #1 YouTube by nearly 79 million unique video viewers.

All of the top 10 U.S. video brands saw an increase in unique video viewers from the previous month.  The fastest-growing among the top brands – and new to the top 10 during March – was CNN Digital Network with a 60 percent increase in unique U.S. video viewers.

CNN Digital Network was also new to the top 10 most heavily used brands in March and saw the largest month-over-month growth in streams (+128%), mostly due to U.S. video viewers streaming coverage of the earthquake and tsunami in Japan.  Also showing significant gains in streams from last month were Netflix (+28%), MTV Music Networks (+25%), VEVO and Yahoo (+21%).

Netflix is once again the most engaging video brand in the U.S. as video viewers averaged nearly 10 hours on the site from home and work locations.  Justin.tv’s U.S. video viewers showed the largest month-over-month increase in time spent viewing video on the site, up 17 percent from February.

*updated April 18, 2011 to clarify and correct chart references to unique viewers, total streams and time per viewer.

The same video brands from last month are still the most popular in February, but with a slight change in ranking as VEVO moved past Facebook to take the #2 spot with 32.3 million unique video viewers.

Despite the short month, Hulu had the largest increase in audience among ten most popular brands, up 7.3 percent to 12.8 million unique viewers. Along with VEVO and Hulu, AOL Media Network and Fox Interactive Media also saw gains in unique U.S. viewers, up 6.8 percent and 6.1 percent, respectively.

CBS Entertainment Websites was new to the ten most heavily used brands in February with a 22.5% increase in total streams from last month. MTV Music Networks also showed notable month-over-month growth in streams, up 15.6 percent from January.

Among the ten most engaging video brands, Cwtv.com’s U.S. video viewers showed the largest month-over-month increase in time spent on the site from home and work locations, more than doubling their average time spent in January. The #2 site Tudou.com also saw significant growth as video viewers increased their time on the site by 25 percent, spending 8 hours, 8 minutes on average in February.