It could only happen in cyberspace. Someone commits a crime and posts the evidence online for the world to see.

Take the case of the two Florida teens who played the so-called fire-in-the-hole prank on a fast food restaurant employee, tossing a 32-ounce soda through a drive-through window. They posted a video of it on YouTube, bragged about it on MySpace -- and were tracked down through their own user-generated digital footprints. In a perfect stroke of Web justice, the judge ruled that as part of their sentence, the pair had to film an apology and post it on YouTube.

The unedited and uncensored nature of user-generated Web content is a double-edged sword -- freedom of speech and expression versus the dark side of human behavior. With technology allowing everyone to share almost everything, the Internet has become a global gathering spot for gossip and voyeurism, a place that can inform, titillate, amuse and, in some cases, harm.

So-called "kid fights" have become a genre unto themselves -- countless numbers of them, involving teens on down to small children, can be found on the Internet. Earlier this year, a group of Florida high school students videotaped themselves beating up a student and posted it online, one of several such teen beatings around the country posted on video sharing sites.

This kind of teen violence may not be new, but the idea of putting it online is. It comes naturally to a plugged-in, text-messaging generation accustomed to recording their every move on digital video cameras or cell phones to share with others.

Los Angeles-based media observer Michael Levine blames technology itself for the phenomena of sharing -- and watching -- online violence.

"As we become a more and more technologically sophisticated culture, we also by definition become less reverent,'' he said. "With technology, you're almost worshipping the man-made as opposed to the divine. We're all so busy and distracted. Distracted people are not contemplative, reflective people."

User-generated content has become the new online legal battlefield, from copyright and trademark violations -- the most common reason why content is removed -- to uglier online posts such as cyberbullying, stalking, gossip and slander -- even terrorist activity.

A survey this month of 1,500 Americans by Rasmussen Reports found nearly half believed the federal government should regulate the Internet the way it does television and radio, and 73 percent said Internet harassment should be a crime.

Connecticut Sen. Joseph Lieberman's efforts to get al-Qaida and other terrorist training, recruiting or propaganda videos removed from YouTube, where graphic videos of suicide bombings and beheadings have been posted, drew attention to the potential for the use of video sharing sites by terrorists.

YouTube did remove about 80 videos, Mr. Levine said. "It's a great start. But it's not enough. Whether you venerate the First Amendment or not, this is perceived by many as aiding and abetting terrorism. Does a free society or a company within a free society have a right or obligation to limit some of this nefarious behavior?"

YouTube's policy prohibits inappropriate content -- including pornography, graphic or violent images in videos in which people are hurt or humiliated, and hate speech -- and relies on the user community to police it.

Rules for content are posted in the site's community guidelines section. Users flag content they feel is offensive or inappropriate, and YouTube reviews the flagged content and removes it if it violates guidelines. Repeat offenders' accounts are disabled.

Others use the Internet to harass their targets psychologically, and lawmakers are moving to stop these kinds of crimes.

In 2006, a 13-year-old Missouri girl committed suicide after being harassed on the Internet -- a case that this month led to charges against a mother who prosecutors allege drove the teen to it. In May, the Missouri legislature enacted a law redefining harassment to include Internet postings and computer messages along with written messages or telephone calls.

Cyberstalkers use the Internet to intimidate or harass their targets. They may send unwanted e-mails to their victims or impersonate them in chat rooms. The stalking can also extend offline with physical threats.

Another variation of harassment is the blog stalker. Bloggers, who often post personal details about their lives, are easy targets for those who may be offended by something they've posted, or who use information they've culled about them on their blogs to harass them online and offline.

In April, state Sen. Jane Orie, R-McCandless, introduced an amendment incorporating cyberbullying into Pennsylvania law covering crimes and offenses. The new law -- yet to be voted on -- would include online harassment or stalking, or using the Internet to intimidate or defame students or school employees, or to threaten or incite violence against them.

She's also in the preliminary stages of drafting new legislation that would punish those who record kid fights or beatings on camera or cell phone. Even if they don't take part in the actual crime, by recording it and posting it, "they become accomplices," she said.

Ms. Orie says that current laws don't always encompass the nature of crimes in cyberspace, and that making the Internet safer for users is a challenge for lawmakers in every state.

The rise of gossip sites, and social networking sites such as MySpace and Facebook where people post personal information about themselves, raises new legal questions about how to define defamation.

Ms. Orie says the creation of fake MySpace pages with false information about other people and gossip sites is slander and defamation. "People try to say this is free speech. But this goes much further. This is on the Internet for a lifetime."

"Courts around the world are creating Internet law right now -- a process that is both exciting and frightening to watch," says technology law site Bitlaw. "Unlike other areas of commerce that can turn to historical traditions to help settle disputes and guide the development of the law, the law of the Internet has no history to fall back on.

"'Cyber law' is instead being developed by judges who must do their best to fit legal disputes into preexisting legal frameworks. As a result, the legal principles governing conduct and commerce in cyberspace are still in a state of flux."