Social networking sites and blogs are now the fourth most popular online activity and are growing in popularity twice as quickly as traditional online pursuits, such as email and searching, a new report says.

The Nielsen Online research, published Monday, found that 67 per cent of web users visit social networks and blogs, which now account for 10 per cent of all time spent on the Internet.

Social network sites and blogs, which the study also called "Member Communities," have overtaken email and are now behind only search engines, general interest portals and software applications in the list of most popular online pursuits.

"Social networking has become a fundamental part of the global online experience," John Burbank, CEO of Nielsen Online, said in a statement. "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."

Searching continues to be the most popular online activity, according to the report, with a global reach of nearly 86 per cent, followed by general interest portals with 85.2 per cent and software manufacturers with 73.4 per cent.

Email grew by 2.7 per cent between December 2007 and December 2008, the study period, while search engines and portals grew by 1.9 per cent each.

However, those figures were eclipsed by member communities, which grew by 5.4 per cent in the same period.

Facebook, which has 175 million users, posted the highest growth in the social networking sector, with 20.5 billion minutes spent on the site in 2008, up from 3.1 billion minutes in 2007.

While it may seem that social networking sites and blogs are enjoyed mostly by teens and younger adults, the report found that the largest increase in visitors to these sites was among the 35-to-49-year old age group, with a boost of 11.3 million users.

The study has implications for the news media and advertisers, the report said, as member communities offer a new way to connect with their audiences.

"Social networks are ultimately about friendships, where members add value to each other's lives through interaction," the report said. "Therefore, advertising should follow the same philosophy of adding value through interaction and consultation."