Growing up I heard this phrase uttered over and over by teenage girls and teenage boys who had heard a nasty rumor about themself that someone else started. When the eventual confrontation takes place, it almost always starts with something along the lines of, "Say it to my face".
Blogs and message boards have provided a sounding board for people to post things that they would probably never write if they actually had to sign their real name to it. What ends up happening is people think that they can say anything they want without the fear of any type of retribution. This feeling of immunity gives people internet courage. They believe they can say anything they want without fear of retribution because of this anonymity. This is about to change.
In Indiana, defamation lawsuits against individuals that have posted defamatory comments on a newspapers comments section have been filed. In fact a Marion County Judge in the past few weeks ordered two newspaper-owned websites to hand over identifying information about the authors of pseudonymous online posts.
Here is an article discussing the situation, and I expect you will see more and more of these type lawsuits across the country. Hopefully people will realize that you can be held accountable for what you say on the internet.