Nielsen Online finds that the amount of time U.S. Internet users spend on social networking sites was up some 83 percent in April of 2009 compared to April of 2008…but that social networking’s growing audience is also a very fickle crowd, prone to rapidly shift away from services as they lose popularity or fall from favor.
"Remember Friendster? Remember when MySpace was an unbeatable force?” asked Nielsen Online’s VP for media and agency insights Jon Gibs, in a blog posting. “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."

