According to The Nielsen Company, consumers all over the globe spent an average of more than five and half hours on social networking sites in December 2009. This represents a huge 82 percent jump from December 2008, when the average was three hours.  

Globally, social networks such as Facebook and Twitter and blogs are the most popular online category, when Nielsen compared time spent on sites. In second place were online games, followed by instant messaging. Facebook had nearly 207 million unique visitors in December, the most of any of the sites. In fact, 67 percent of all social media visitors came to Facebook during the month.  

Here are additional statistics from NielsenWire.