MILPITAS, Calif.—When Kevin Jenkins wanted to teach his fourth-grade students at Spangler Elementary here how to use the Internet, he created a site where they could post photographs, drawings and surveys.

And they did. But to his dismay, some of his students posted surveys like “;Who's the most popular classmate?”; and “;Who's the best-liked?”;

Jenkins' students “;liked being able to express themselves in a place where they're basically by themselves at a computer,”; he said. “;They're not thinking that everyone's going to see it.”;

The first wave of parental anxiety about the Internet focused on security and adult predators. That has given way to concerns about how their children are acting online toward friends and rivals, and what impression their online profiles might create in the minds of college admissions officers or future employers.

Incidents like the recent suicide of a freshman girl at South Hadley High School in Massachusetts after she was bullied online and at school have reinforced the notion that many children still seem unaware how the Internet can transform typical adolescent behavior—cliquish snubs, macho boasts, sexual flirtations, claims about drinking and drugs—into something not only public, but also permanent.

The South Hadley case is leading some states to re-examine their laws against bullying; while more than 40 states address the issue, they tend to focus on punishment, not prevention.

Jenkins this year began using lessons from Common Sense Media, which cautions students to consider their online behavior before they get into trouble.

Financed largely by foundation money, Common Sense will offer a free curriculum to schools this fall that teaches students how to behave online. New York City and Omaha have decided to offer it; Denver, the District of Columbia, Florida, Los Angeles, Maine and Virginia are considering it.

“;You want to light a fire under someone's fanny?”; said Liz Perle, editor in chief of Common Sense Media. “;Have your child post something that is close to a hate crime.”;

And the Internet is where children are growing up. The average young person spends seven and a half hours a day with a computer, television or smart phone, according to a January study from the Kaiser Family Foundation. Considering that the time is mostly outside of school, the results suggest that almost every extracurricular hour is devoted to online life.

Common Sense's classes, based on research by Howard Gardner, a Harvard psychology and education professor, are grouped into topics he calls “;ethical fault lines”;: identity (how do you present yourself online?); privacy (the world can see everything you write); ownership (plagiarism, reproducing creative work); credibility (legitimate sources of information); and community (interacting with others).

Raquel Kusunoki, a sixth-grade teacher at Spangler, recently asked Jenkins, now an educational technology specialist for the school district, to teach Common Sense classes to her students. The class listened as Jenkins read a story about a girl who got annoyed when her parents quizzed her about details from her online journal.

Lucas Navarrete, 13, asked, “;What's their right to read her personal stuff?”;

“;Maybe they're worried,”; suggested Morgan Windham, a soft-spoken girl.

“;It's public!”; argued Aren Santos.

“;OK, OK, if it was a personal diary and they read it, would you be happy?”; Lucas asked. “;They have no right, see?”;

Jenkins asked the class if there is a difference between a private diary on paper and a public online diary. But the class could not agree.

“;I would just keep it to myself and tell only people that were really, really close to me,”; Cindy Nguyen said after class. “;We want to have our personal, private space.”;

That blurred line between public and private space is what Common Sense tries to address.

“;That sense of invulnerability that high school students tend to have, thinking they can control everything, before the Internet there may have been some truth to that,”; said Ted Brodheim, chief information officer for the New York City Department of Education. “;I don't think they fully grasp that when they make some of these decisions, it's not something they can pull back from.”;

Common Sense bases all its case studies on real life, and insists on the students' participation. “;If you just stand up and deliver a lecture on intellectual property, it has no meaning for the kids,”; said Constance M. Yowell, director of education for the John D. and Catherine T. MacArthur Foundation, which has provided financing.

But some media experts say that in focusing on social issues, Common Sense misses some of the larger, structural problems facing children online.

“;We can't make the awareness of Web issues solely person- and relationship-centered,”; said Joseph Turow, a professor at the Annenberg School for Communication at the University of Pennsylvania. Children should learn things like what a cookie or a Web virus is, and how corporations profit from tracking consumers online, he said.

In San Francisco, the Schools of the Sacred Heart, related boys' and girls' schools, met with parents earlier this year to discuss their Common Sense pilot program with Sister Anne Wachter, the head of the girls' school.

“;The messes they get into with friends, or jumping onto someone's site and sending a message,”; she said. “;They don't know, sometimes, how to manage the social, emotional stuff that comes up.”;

Crowded into a basement math classroom, the parents listened to a teacher, Bill Jennings, discuss lessons he had been trying. In front of Wachter and the parents, many of whom are Catholic, he gave an example of a social-networking message the girls might see about a new student: “;Amy is a slut; her mom's a whore.”;

There was startled silence from the parents.

“;If I came up with five scenarios for Maya, they'd probably be so far from that—they're not calling someone's mother a whore,”; said Sheila Chatterjee, a parent of a seventh grader.

“;But the language of that is what they hear,”; Jennings said.

“;It's authentic,”; Chatterjee agreed.

Shirin Oshidari, who has a son in seventh grade, said this lesson seemed obvious. “;To me, it's exactly how you behave person to person,”; she said. “;Everything you write, the college you want to go to, they will see it. And the job you want to get, they will see it.”;

Jaime Dominguez, the head of the boys school, said: “;The hard part is, as adults we see that connection. They don't.”;