This year, more than two dozen teens in at least six states have been investigated by police for “sexting” — sending nude pictures of themselves in cell phone text messages — which carries a charge of distributing child pornography.

More tragically, a suicide in Ohio occurred last year after a girl who sexted her picture to a boyfriend was humiliated when the boy forwarded it to hundreds of kids.

These cases don’t surprise Jim Steyer, 52, the founder and CEO of Common Sense Media, a nonpartisan, nonprofit based in San Francisco. The www.commonsensemedia.org Web site gets more than 2.5 million hits monthly for its parent-centric reviews of movies, TV, books, video games, music and Web sites.

In fact, he expects that without teaching Internet literacy, we’ll see even more Internet crises, like the cyberbullying that was blamed for the suicide of a 13-year-old girl in 2006, as a new generation grows up in a virtual world with dangers they don’t understand.

And that, he said during a recent visit to The Hockaday School in Dallas, is why his company launched the Common Sense Schools Parent Media Education Program in November. More than 1,000 schools have signed up for the program, which gives parents and educators tools to help kids learn to think before they post pictures and send texts that can be seen by a vast public and never go away.

“The Internet is the place where all the kids are. They know how to work it, which gives them a false sense of confidence,” Steyer says. “But they don’t always have the experience and judgment to make good decisions. And most parents are clueless. They don’t understand the technology because they weren’t raised with it.”

There was a time when parents could control a child’s Internet use by putting the computer in a central location. But now kids can use their phones to get on the Internet, he points out. As if in tacit illustration of his point, one Hockaday girl showed how she could text without looking at the keys with her phone hidden in her pocket.

Steyer is a onetime civil rights attorney with the NAACP Legal Defense Fund and professor at Stanford University for the past 19 years. When he founded Common Sense Media five years ago, his main concern was about the role of television in children’s lives.

A father himself — he has four children — he had written a book, “The Other Parent: The Inside Story of the Media’s Effect on Our Children” in 2003, concerned with the growing role of the media was in the lives of children. Chelsea Clinton, then a student at Stanford, wrote the afterword. When Steyer told her father, President Bill Clinton, Sen. Joseph Lieberman and Sen. John McCain that someone should do something to protect kids, they told him to do it.

So he did. But as the years have passed, his concerns shifted from television and video games to the Internet, where he now helps parents navigate the emergence of Facebook, YouTube, MySpace, Twitter and Club Penguin — a Facebook for the younger set. And he expects that the number of new outlets will keep growing.

The Internet isn’t going away. Nor does he advocate that it should.

“I teach sanity, not censorship,” he says. “I believe in the First Amendment. I believe that we can achieve a really good quality of life for the kids if you have reasonable restrictions and teach them good critical thinking skills — it’s always a balancing process.”

The goal of Common Sense Media is to help kids and parents navigate this brave new world with responsibility, ethics and intelligence, Steyer stresses. He wants to take his experience fighting for civil rights and use it to advocate for children.

“I want to turn Common Sense into the equivalent of the AARP for children,” he says.

And to keep up with rapid pace of Internet developments, he makes it a point to keep learning from his students and his kids about the latest developments.

“My kids are always teaching me new stuff. They program my iPhone for me. I listen to them and respect their point of view, but I also let them know when I find things that are troubling. That’s what parents need to do.”