Now visited by over two-thirds (67 percent) of the global* online population, “Member Communities,” which includes both social networks and blogs, has become the fourth most popular online category – ahead of personal email. It is growing twice as fast as any of the other four largest sectors (search, portals, PC software and email), according to The Nielsen Company’s“Global Faces and Networked Places,”a comprehensive report published today revealing the new global footprint of social networking.

“Social networking has become a fundamental part of the global online experience,” says 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. Social networking will continue to alter not just the global online landscape, but the consumer experience at large. This study explains why.”

According to the Nielsen report, Facebook - the world’s most popular social network - is visited monthly by three in every 10 people online across the nine markets in which Nielsen tracks social networking use. Orkut in Brazil has the largest domestic online reach (70 percent) of any social network in these markets.

The report, available today, provides insights into the changing size and audience composition of the global social networking audience and the increasing share of Internet time for which it accounts. The report also analyzes how the major players are faring and what advertisers and publishers can do to take advantage of the social network phenomenon.

Other key findings include:

• One in every 11 minutes online globally is accounted for by social network and blogging sites.
• The social network and blogging audience is becoming more diverse in terms of age: the biggest increase in visitors during 2008 to “Member Community” Web sites globally came from the 35-49 year old age group (+11.3 million).
• Mobile is playing an increasingly important role in social networking. Nielsen found UK mobile Web users have the greatest propensity to visit a social network through their handset, with 23 percent (2 million people) doing so, compared to 19 percent in the US (10.6 million people). These numbers are a big increase over last year – up 249 percent in the UK and 156 percent in the US.

Social networking isn’t just growing rapidly, it’s evolving - both in terms of a broader audience and compelling new functionality,” says Alex Burmaster, author of the study and Communications Director across EMEA for Nielsen Online. “We felt compelled to analyze the state of the social networking market globally and consider what implications this has for our publisher and advertiser clients.”