Long ago and far away, back when the Internet first started gaining traction as a public communications medium, a cartoon depicted a dog logging onto a computer with a caption that read: "On the Internet, nobody knows you are a dog." The clear implication was that the Internet was a new playground where communications could be free and anonymous. But is that really the case as the Internet has matured? Not necessarily.

It is true that people have aconstitutional right of free speech. Indeed, that right has been interpreted by courts to allow for free online anonymous speech - but to a point. While people can say what they want on the Internet without providing their true identities, perhaps operating under pseudonyms, their identities can be unmasked under certain circumstances.

The right to free online anonymous speech potentially ends when that speech is defamatory. If what is posted online and is false, and causes harm the true identity of the online communicator can be unmasked.

For example, let's say hypothetically that a person with the true name John Smith sets up a Web site and on that site under the pseudonym "Consumer Crusader" he proclaims that a well-known fast-food chain serves rat instead of chicken as represented in its fried food offerings. Continuing with the hypothetical, let's assume that as a result of the hysteria whipped by this site, there is a large drop off in the number of customers that go eat at the chain's restaurants and that the share price of the chain plummets. Can John Smith's anonymous free speech rights protect him from being unmasked as the person behind the Consumer Crusader and associated Web site?

Well, first the fast-food chain likely would file a defamation lawsuit against a "john Doe" defendant - the person behind the Consumer Crusader whose identity is not yet known. The idea would be to substitute in the true name of this defendant (John Smith) in the lawsuit once his identity is ascertained.

Next, the fast-food chain would subpoena the ISP that hosts the Consumer Crusader's Web site for his identity. The ISP then would give John Smith notice that his identity will be revealed pursuant to the legal process of the subpoena unless John Smith timely files a motion to quash.

If John Smith files such a motion, he would argue that his online anonymous free speech rights trump any interest in obtaining his true identity. Obviously, while making this motion to the court, he still would be operating under a fictitious name. The fast-food chain would counter this argument by setting forth the falsity of the online statements made and the harm suffered.

Ultimately, if the court finds that the fast-food chain has made out a prima facie case of falsity and harm, John Smith's identity would be unmasked and his name would be added as the true defendant in the defamation lawsuit, and he then would have to defend the case. Of course, if his identity is not unmasked, the lawsuit essentially would end, as there would be no true defendant to go after.

In this particular hypothetical, it is highly likely that John Smith's identity would be unmasked, and if he were a dog, that would come out, contrary to what was suggested in the cartoon.

The lesson learned is that people should not take comfort that they can say whatever they want without implication on the Internet, even if they do have some rights of anonymous online speech.