(AP) -- It's not Big Brother, but "big business" that Internet users are more worried about. A new survey found that nearly half of Internet-connected Americans age 16 and older worry about businesses checking what they do online. By comparison, 38 percent worry about the government doing so.

Not that those concerns are stopping people from using the Internet for shopping, social networking and a smattering of other activities.

The latest study from the Center for the Digital Future at the University of Southern California found that 82 percent of Americans use the Internet, the same as in 2009.

On average, they spend more than 18 hours a week online - for browsing the Web (79 percent), for banking (47 percent) and for social networking and video-sharing (46 percent).

In the decade that the Digital Future researchers have been tracking Americans' Internet use, social networks were born, and many of them all but died (anyone remember Friendster?). People have gotten used to migrating more of their activities online and accessing the Internet from more devices than ever.

"When we started our work 11 years ago, the Internet was almost completely PC-based. We used to compare it with TV," said Jeffrey Cole, director of the Center for the Digital Future.

People would use the Internet - dial-up service, back then - the way they watched TV: sitting down in front of the screen for 30, 60 minutes at a time.

Not any more.

"We think PCs are slowly going away" except for the heaviest users, such as those using it for computer-assisted design, editing or heavy writing, Cole said. "Wireless, mobile Internet is becoming the Internet for most people."

Among other findings in the survey, conducted from April 27 to Aug. 30, 2010:

- Of the 18 percent of Americans who are not using the Internet, 7 percent cited cost as a reason. A quarter said they don't go online because they don't find it useful or have no interest. And 37 percent said they didn't have a computer or Internet connection.

- 21 percent of non-users said they were excluded from communications among their friends and disadvantaged in obtaining information for work, studies or hobbies as a result of not going online. Still, 66 percent of them said they are not likely to go online within the next year.

- 68 percent of adult Internet users go shopping online. Books and gifts are the most popular categories, followed by clothes and travel.

- People are still worried about privacy when shopping online, though fewer respondents said they were very concerned or extremely concerned than the year before: 48 percent compared with 54 percent in 2009.

- Email is still nearly universal. Even the texting generation uses this somewhat antiquated method of communication: 98 percent of Internet users under 17 said they email, compared with 95 percent of those aged 18 to 24. The lowest level of email usage, 94 percent, was among 45 to 54-year-olds.

The latest survey of 1,926 people aged 12 and older has a margin of error of plus or minus 2.2 percentage points.

A separate survey, from the Pew Internet & American Life Project, found recently that 13 percent of adult Internet users have used Twitter, up from 8 percent in November 2010. A higher percentage of African Americans and Latinos use Twitter than white people - 25 percent, 19 percent and 9 percent, respectively.

The Pew survey was conducted April 26 to May 22 among 2,277 adults and had a margin of error of plus or minus 3.7 percentage points.

Explore further Eight percent of online Americans use Twitter: Pew

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