Computerworld — Sorry, e-mail. You've just taken a back seat to both social networks and and online games.

Social networks had already surpassed e-mail use among American Internet users . But according to a Nielsen Co. survey released this week, online gaming is now also more popular that e-mail.

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According to the Nielsen survey, Americans today are spending nearly a quarter of their online time posting comments, pictures and video on social networking sites like Facebook and Twitter, making it the most popular online activity among Americans.

Online gaming is the second most popular online activity, accounting for 10% of online use, while e-mail ranks third at 8.3%. In a survey completed in June, 2009, e-mail was the second most popular online activity, accounting for 11.5% of Inernet activity.

"Despite the almost unlimited nature of what you can do on the Web, 40% of U.S. online time is spent on just three activities -- social networking, playing games and e-mailing -- leaving a whole lot of other sectors fighting for a declining share of the online pie," said Nielsen analyst Dave Martin in a statement.

Social networking saw a 43% uptick in usage from June 2009 to this past June -- from 15.8% to 22.7%.

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Late last month, Facebook CEO Mark Zuckerberg announced that the site had snagged its 500 millionth user, cresting another major corporate milestone. In May, Twitter hit a milestone of its own as its users posted nearly 2 billion tweets during the month.

Some recent studies found that some people acknowledge being addicted to sites like Facebook and Twitter.

A study released by Retrevo Inc. in March showed that 48% of online users say they update Facebook or Twitter during the night or as soon as they wake up. And the survey by the consumer electronics shopping and review site found that 32% of respondents see no problem with interrupting a meal to read or send an online message.

And The Oxygen Media Insights Group, a creator of television channels and Web sites for women, released a report last month showing that a growing number of women admit to being addicted to social media .

In the latest Nielsen study, users spend 4.4% of online time viewing portals, making it the fourth most popular destination category, and 4% instant messaging. The share of both portal and instant messaging use declined significantly from 2009, Nielsen said.

Sharon Gaudin covers the Internet and Web 2.0, emerging technologies, and desktop and laptop chips for Computerworld. Follow Sharon on Twitter at @sgaudin , or subscribe to Sharon's RSS feed . Her e-mail address is sgaudin@computerworld.com .

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