Cyberbullying isn't just a problem among adolescents. Adults engage in it, too. From online vigilantism and angry blogs to e-stalking and anonymous ranting on newspaper Web sites, grownups can be as abusive as the meanest schoolhouse tyrant.

The suicide of 13-year-old Megan Meier in 2006 thrust adult cyberbullying into the open. The Dardenne Prairie, Mo., girl killed herself after receiving cruel messages on MySpace from impostors posing as a 16-year-old boy named "Josh Evans."

Lori Drew, the mother of one of Megan's friends, was accused of participating in the hoax along with her teenage daughter and a former teenage employee. Drew has denied sending messages to Megan.

While questions remain about Drew's role, the case has left no doubt that the Internet is rife with adult cyber passion.

After the suicide came to light, an outraged mother several states away ferreted out Drew's identity and posted it on a blog.

Soon, "an army of Internet avengers ... set out to destroy Lori Drew and her family," forcing them from their home and "vowing them no peace, ever," newspaper columnist Barbara Shelly wrote. "Who are these people who have made it their business to destroy her? They are a jury with laptops, their verdict rendered without insight into the dynamics of two families or the state of mind of a fragile 13-year-old girl or even a complete explanation of what actually occurred."

Internet shaming is a growing cultural phenomenon, but Daniel Solove, a professor of law at George Washington University and author of the 2007 book "The Future of Reputation: Gossip, Rumor and Privacy on the Internet," said it can backfire.

"Internet shaming is done by people who want actually to enforce norms and to make people and society more orderly," he said. But instead, "Internet shaming actually destroys social control and makes things more anarchic, and it becomes very hard to regulate and stop it."