According to a new report from market research firm Nielsen Online, which tracks time spent online visiting different websites, social networking websites such as Facebook, MySpace and Twitter is now the most popular web activity, surpassing even email.

Nielsen's global study of social networking, released this week, found that 67 percent of online users spend time on social networks, compared to 65 percent who use email to communicate - among all Internet users worldwide, two thirds visited a social networking site in 2008.

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

According to the report, interest in the "member communities" category, which includes both social networking and blogging sites, is growing four times faster than the other top four sectors, and shows no signs of slowing.
 
"Social networking will continue to alter not just the global online landscape, but the consumer experience at large," he added. Of these social networking sites, Facebook has highest average time per user.

Nielsen measures interest in categories by the percentage of the web audience that regularly visit such sites.

Examining nine global markets, Nielsen Online found that penetration for social networks and blogs was highest in Brazil where 80 percent of the online audience visited such sites. That compares to 75 percent for runner-up Spain and 67 percent for the USA. 

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.