Former ABC newsman Pierre Salinger learned this lesson the hard way when he was fooled by a "bogus" story claiming that the U.S. Navy had been responsible for the downing of TWA Flight 800 in July 1996. Salinger made front-page news with his allegations until it was pointed out to him that his only source was an email message discredited long ago. This was not the first time someone had been taken in by "bogus news" found on the Internet, either. But this was one time that the person involved certainly should have known better!).
A number of Usenet email messages have a lot in common with tabloid journalism. Tales of governmental plots and conspiracies are rampant, along with rumors of every sort. Usenet lends itself to the cultivation of "urban legends" precisely because it is a direct form of communication, bypassing any editorial control which may be exercised by newspaper and magazine editors. (This is why a number of the more responsible Usenet newsgroups are moderated.)
Once a message has been sent, it takes on a life of its own.
Usenet (like its successors chat and instant messaging) is literally like an inviting soapbox where one can express his views (politically correct or not) to his heart's content with little fear of contradiction. Someone wanting to dispute a particular message can only post a later message and hope that the second message chases the first through cyberspace. This is very appealing to those who distrust the media, the "establishment", the government, etc. Think "talk radio" but on a global scale.
While Usenet may be more vulnerable (due to its very nature) to dubious "news", the World Wide Web has had its share of misrepresentation, too. If you read something on a Web page that looks too good to be true, it probably is (meaning, yep, it's a fake!).
Fortunately, the police have computers as well and have started taking people to court who make fraudulent claims on Web pages, just as they would prosecute for fraudulent statements made by other means (such as through newspaper or television ads). Laws against fraud apply online just as they do regarding printed or broadcast material.
So just remember that it is still true that just because you read about something online that (by itself) does not make it so.
Skepticism - don't leave home without it!