The number of minutes spent on Facebook in the last year leapt 700%. MySpace fell 31% but remains the top site for video.
In the US alone, total minutes spent on social networking sites has increased 83% year over year. That growth was led by Facebook as it grew from 1.7bn minutes in April 2008 to 13.9bn in April 2009, making it the number one social networking site for the month.
Facebook was firmly ensconced in the number one spot followed by MySpace, the Google-owned Blogger, Tagged.com and Twitter, which saw explosive growth in the last 12 months as it jumped into fifth place.
While Facebook rules in the social networking space (April was the fourth month in a row that Facebook held the top spot in both unique visitors and total minutes) MySpace has been winning in online video.
With 120.8m video streams, Myspace.com is the undisputed king when it comes to social networking destinations when ranked by streams and total minutes spent viewing video -- giving some cheer to new MySpace CEO Owen Van Natta.
MySpace visitors spent 384m minutes viewing video on the site, with an average of 38.8m per viewer.
In comparison, Facebook visitors spent only 113.5m minutes viewing video in April, with an average of 11.2 m per video viewer.
However, despite the impressive growth of Facebook and Twitter Nielsen warned that both services could find themselves quickly replaced as users move on to the next big thing as has happened to rival services in the past.
Jon Gibs, vice president, online media and agency insights, at Nielsen Online, said: "The one thing that is clear about social networking is that regardless of how fast a site is growing or how big it is, it can quickly fall out of favour with consumers.
"Remember Friendster? Remember when MySpace was an unbeatable force? Neither Facebook nor Twitter are immune.
"Consumers have shown that they are willing to pick up their networks and move them to another platform, seemingly at a moment's notice."