By now, the targeted girl had become more self-confident. She was furious that the bully escaped punishment. When the bully began picking on a second, weaker girl, she grew further incensed.

One bristling morning, the two girls came to blows, which the bully sorely came to regret. Although teachers quickly broke up the fight, word of the outcome spread more swiftly:

“All the kids chanted the victim’s name,” Mr. Orsini said, “in triumph in the lunchroom.”

The Cybersages

What a difference a few years can make in the life of a tween.

Earlier this month, a proud posse of Benjamin Franklin eighth-grade girls strode into homerooms of sixth graders: inches taller than the 12-year-olds, skin calmer, they radiated a commanding exuberance as they tossed their long, glossy manes. They wanted to offer advice about social networking sites and cyberbullying.

“How many of you have discussed Mr. Orsini’s letter with your parents?” asked Annie Thurston, one of the eighth graders, referring to his admonitions about online activity.

Slumped in their desks, at least a dozen students in one class glumly hoisted their hands.

In April, a parent alerted Mr. Orsini about Formspring, a site on which comments can be sent anonymously to mailboxes, and posted at the mailbox owner’s discretion. Many adults seem confounded at why girls, in particular, would choose to post the leering, scabrous queries; some teenagers say they do so in order to toss back hard-shelled, tough-girl retorts.

The principal found the names of some Benjamin Franklin students on Formspring. As Mr. Orsini later recounted the experience, he couldn’t bring himself to utter even a sanitized version of the obscene posts he had read. His face reddened, tears filling his eyes.