As more students spend large chunks of study and leisure time online, schools across the USA are adding coursework focused on privacy, cyberbullying and electronic plagiarism.

Many schools not only are incorporating Internet safety into lesson plans but also shifting their focus from the pervasive "stranger danger" message typically given to young computer users.

The idea, says Principal Chris Lehmann of Philadelphia's Science Leadership Academy, is teaching students to be better "digital citizens." Freshmen at his public high school are required to take a course in how to watch their digital footprint — in other words, to be careful what they say on the Internet.

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"All of the drama, all of the growing up, all of the growing pains, all of the things we know happen in high school now also happen digitally," Lehmann says. "Think of every mistake you made as a teenager. Now imagine making that mistake in a permanent public forum."

Many schools around the country have adopted similar coursework. For instance, at Schwenksville Elementary School near Philadelphia, librarian Joan Curtis teaches fifth-graders how to recognize bogus websites using a fake but realistic "Librarian of the Year" site she created.

At Gresham-Barlow Web Academy, a charter middle- and high school near Portland, Ore., all middle-schoolers are required to take an online safety course that covers topics including cyberbullying, plagiarism and online "ethical behavior," Principal Michael Harris says.

The digital training comes as research shows that Web usage is virtually ubiquitous among kids. Though most students say they generally access the Internet from home, 75% of teens say they go online at school, too.

New findings show that even young children spend time online. A national survey released in October by the non-profit Common Sense Media found that 41% of children 8 and younger have access to a smartphone and 13% have spent time on social networking sites and virtual worlds.

Schools teach students to be wary of whom they meet online. Harris says educators are concerned about older students as well as younger ones. "Even though they're 15, 16 years old they're still pretty vulnerable," he says.

Statistics show that online predation is rare — a Harvard study sponsored by attorneys general in all 50 states found that being online "increases the availability of harmful, problematic and illegal content but does not always increase minors' exposure." It said kids most at risk are those who "often engage in risky behaviors" and have difficulties in other parts of their lives.

"The whole 'stranger danger' thing was very much driven by parental alarm," says Barbara-Jane Paris, principal of Canyon Vista Middle School in Austin, who testified before Congress in 2010 on cyberbullying.

The challenge, she and others say, is teaching kids that what they say and do online can have immediate, profound consequences — and that an offhand cruelty or indiscretion can last forever.

"You can't indefinitely call somebody a (slur for gays) and then just say, when called to the table, 'I was only kidding,' " Paris says.