A woman receives an email containing an article that paints a couple of doctors in an unfavorable light and decides to post it up in a pair of online newsgroups for discussion. It happens a lot, right? This time, the doctors sued for defamation of character. The appeals court decision may have originally sided with the defamed, but yesterday the California Supreme Court reversed that call.

It's a weightier case than it seems at first glance. Even though this morning's The Wall Street Journal may have buried the story (you have to get to the bottom of page B5 to see the three short paragraphs), it was something that was definitely on the minds of many Internet companies.

The whole Web 2.0 movement revolves around user-generated content, and finding individuals culpable is just one step away from faulting the dot-com giants that house the platforms.

Want a little more flesh on the bone? OK, consider some of these common occurrences in cyberspace:

  • On Amazon.com (NASDAQ:AMZN), someone pens a scathing review of the latest John Grisham book; the book's sales stumble.
  • At Expedia's (NASDAQ:EXPE) TripAdvisor.com, a disappointed traveler goes into excruciating detail about the uncleanly state of a motel off the Vegas strip.
  • The Yahoo! (NASDAQ:YHOO) message boards light up with accusations of improprieties at a heavily shorted company.
  • A diner has a horrendous table experience at a trendy Hollywood eatery and rips into the restaurant on CNET's (NASDAQ:CNET) Chowhound.

These cases were just made up. (Don't sue me, Grisham!) But it doesn't take long to realize that similar instances happen around the clock online. If website owners had to verify every claim before posting a submission, the Web 2.0 movement would grind to a halt.

Should individuals be liable for their own actions? Most heads would nod in agreement. However, seeing peer-to-peer file-sharing networks get taken down by record label litigation reminds us that there will always be a gray area as to how much a site is to blame for the actions of its constituent community.

Keep watching these cases, though, because gray areas can move around like patchy clouds.

Amazon.com and Yahoo! are Motley Fool Stock Advisor recommendations. CNET is a Rule Breakers newsletter pick.

Longtime Fool contributor Rick Munarriz tries to abide by the golden rule in cyberspace, but nobody's perfect. He does not own shares in any of the companies in this story. He is also part of the Rule Breakers newsletter research team, seeking out tomorrow's ultimate growth stocks a day early. The Fool has a disclosure policy.