Americans are so fixated on social networks that they spend an average of 16 minutes out of every hour on them, according to a study by Experian Marketing Services.
In the U.S., 27% of users' time online is spent on forums and social networks, like Facebook, Twitter and Instagram, Experian said.
Experian included both desktop and mobile users in its study.
It found that the U.S. is a bit more hooked on social networks than Internet users in the United Kingdom, who spend 13 minutes of each hour on social nets, and Australians, who spend 14 minutes per hour.
U.S. social networking numbers have held fairly steady over the last few years. Experian reported that social media took up 30% of Americans' time in 2011 and 27% last year.
Dan Olds, an analyst with The Gabriel Consulting Group, said he's not surprised that people are spending so much time on Facebook, Google+ and Tumblr, despite the fact that there's a treasure trove of information elsewhere online.
"Social networking is essentially flat year-to-year, which I think could be a signal that the social networking wave has crested and that the high growth days are gone, at least in the U.S.," said Olds. "However, social networking is by far the biggest single task occupying people's online time, which shows that social nets have become an integral part of people's lives."
Over the last several years, sites like Facebook and Twitter have gone from being largely used by people who want to post drunken party pictures or cute stories about their cats to sites where users debate politics, support each other during natural disasters and even gather support for political upheaval.
That kind of involvement has lifted the genre head and shoulders above other online activities.
Experian reported that 9 minutes out of the average hour online is spent on entertainment sites; 5 minutes go to online shopping; and about 3 minutes each go to business sites, email and news sites.
The report also noted that about 3 minutes out of an hour are spent on adult entertainment sites.
The Experian study is based on a survey of more than 50,000 mobile users and 10 million Internet users in the U.S. Everyone surveyed was 18 or older.
Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin, on Google+ or subscribe to Sharon's RSS feed. Her email address is email@example.com.
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