Social networks and blogs are now more poplar than email, Nielsen reports. Time spent on them accounts for more than 10 total Internet time, and is growing three times faster than other Internet applications.

One in every 11 minutes online is now spent on social networks and blogs, which Nielsen groups together into what it calls “Member Communities.” This is a four-minute increase over time spent on them in 2007.

Member Communities are now the fourth-most popular Internet category after search, portals and PC software downloads. Email is now the fifth most popular Internet category.

The use of Member Community sites is growing twice as fast as the other four top categories. Between 2007 and 2008, the amount of users of blogs and social networks grew 5.4 percent.

Two-thirds of global Internet users access Member Community sites.

“Social networking has become a fundamental part of the global online experience,” said John Burbank, CEO of Nielsen Online. “While two-thirds of the global online population already accesses member community sites, their vigorous adoption and the migration of time show no signs of slowing.”

The adoption is most aggressive among older adults. The largest increase in 2008 visits was among the 35-49-year-old age group. Interestingly, while the adoption of social networks and blogs is increasing in all demographics over 35, among people 34 and younger, growth is actually shrinking.

By far the fastest growing Member Community is Facebook. While overall time online grew 18 percent in 2008, and time on other Member Community sites rose 63 percent, time on Facebook increased 566 percent. Total time spent on Facebook jumped from 3.1 billion minutes to 20.5 billion.

Facebook has the highest overage time per person of the top 75 brands online.