While a large percentage of adults say they monitor the activity of children in their households on social networking sites such as Facebook, almost 30 percent do not, according to results of the 11th annual study of the impact of the Internet on Americans by the USC Annenberg School for Communication and Journalism’s Center for the Digital Future.

“It’s every parent’s dilemma to know when to trust their children,” said Jeffrey Cole, director of the center and research professor at USC Annenberg. “In the last five years, we have seen many new issues about parenting and technology evolve that previous generations never encountered. How parents cope with their children using social media like Facebook represents only one aspect of these issues.”

The study found that although 70 percent of adults said they monitor the activity of the children in their households while on social networking sites, only 46 percent have password access to the children’s accounts.

The findings also showed that of the adults who do not monitor the social networking activity of the children in their households, 40 percent cite trust as the explanation: Either they trust their children or they believe that monitoring online behavior would show lack of trust. According to the study, 9 percent of adults don’t monitor their children on Facebook because they don’t know how to use the social networking site, and 7 percent don’t because “they don’t have time to do it.”

Jeffrey Cole, director of the Center for the Digital Future at USC Annenberg

When asked at what age the children in their households should have a mobile phone or Facebook account, the adults said the appropriate age was 13 for mobile phones and 15 for a Facebook account.

The responses about parent supervision of children on Facebook are among the more than 180 issues explored in the 2013 Digital Future Project, the longest continuing study of its kind and the first to develop a longitudinal survey of the views and behavior of Internet users and nonusers.

Conducted in conjunction with Bovitz Inc., the current study includes new questions that explore negative online attention, such as bullying, harassment and unwanted sexual attention, as well as a closer examination of the “millennial rift” — the vast differences between how millennials (ages 18 to 34) and nonmillennials use and perceive online sites and services.

Millennial rift

The survey found that millennials, when compared to nonmillennials, have different views about using the Internet and report significant differences in many aspects of their behavior online.

Millennials are more involved with mobile shopping and comparison shopping than nonmillennials. Sixty-eight percent of millennials have done a price comparison on their mobile devices while in a store to find if there is a better deal available online, compared to 43 percent of nonmillennials.

Twice as many millennials (23 percent) as nonmillennials (10 percent) have purchased products online on their mobile devices while in a traditional retail store. Forty-six percent of millennials, compared to 24 percent of nonmillennials, have done an online price comparison in a store to find a better deal at another retail store.

Compared to nonmillennials in the study, millennials as consumers of online media content spend: three times as much time watching movies online; twice as much time listening to online radio; four times as much time watching television online; more than twice as much time watching paid online television services such as Hulu Plus; and almost twice as many watch movies sometimes or often through a fee service such as CinemaNow or Netflix.

More than twice as many millennials as nonmillennials watch online versions of television shows or music videos.In addition, 70 percent of millennials, compared to 51 percent of nonmillennials, value social networking sites such as Facebook, Twitter and Google Plus as important for maintaining their relationships.

Compared to nonmillennials, millennials follow nine times as many companies and brands on Twitter, and “friend” more than twice as many companies and brands on social networking sites such as Facebook.

Changing patterns of online purchasing

The 2013 report also explored a variety of new issues involving online buying, including purchasing on mobile devices and the impact of sales tax on Internet buying.

More than half of Internet buyers (52 percent) said that if their state starts to collect tax for online purchases, they would buy less online, and 9 percent said they would stop buying online altogether. Only 39 percent said that sales tax charged for online purchases would not change their purchasing.

The survey found popular use of mobile devices while shoppers browse in traditional retail stores. Forty-nine percent of Internet purchasers who browse in local retail stores said they have compared prices on a mobile device while in a store to see if there is a better deal available online. Thirty percent of Internet users overall said they have used a mobile device while in a store to determine if a better deal was available at another store nearby. Thirteen percent of online purchasers who browse locally said they have purchased a product online with a mobile device while in a store. Seventy percent of that group made the purchase from a competing online retailer and not from the store’s website.

Problems that cross all age groups

The Digital Future project also explored the darker side of Internet use by asking new questions about online bullying, harassment and unwanted online sexual attention.

A small group of respondents (10.4 percent) said they had been bullied or harassed online. Almost equal proportions of men (10.3 percent) and women (10.5 percent) reported being bullied or harassed online.

Although bullying and harassment of young Internet users has dominated media coverage of this problem, the survey found that measureable percentages of users in all age ranges report that they’ve been bullied or harassed. The largest of these groups was users under 18; 18 percent of them reported being bullied or harassed.

Sixty-eight percent of those who have been bullied or harassed online report that the impact was minor. However, more than 30 percent of those who have been bullied or harassed online said the impact was moderate or worse, and 14 percent said it was serious. That impact was judged moderate or serious by more than twice as many women (21 percent) as men (10 percent).

Compared to the percentage of those who have been bullied or harassed online (10 percent), 21 percent said they have received unwanted sexual attention online. Both men and women receive unwanted sexual attention online; 24 percent of women and 18 percent of men.

While more than one-third of users under 18 reported receiving unwanted sexual attention online, significant percentages of users in all age categories reported it as well.

“Negative online attention — including bullying, harassment, and unwanted sexual communication — produces effects ranging from minor nuisances to tragic consequences,” Cole said. “While prominent cases in the news focus on how negative online attention affects young users, our study found that these issues affect users of all ages; these issues demand continued exploration.”

More stories about: Digital Media