A common misconception is that you cannot be sued for blogging or posting material anonymously or pseudonymously because your identity is forever hidden. In fact, there are legal procedures that individuals, companies, and the government can use to discover the identity of an anonymous or pseudonymous online speaker under certain circumstances.

In the civil litigation context, the legal system provides for a kind of lawsuit called a "John Doe" lawsuit, in which a plaintiff sues an unknown defendant -- for example, an anonymous blogger who allegedly libeled the plaintiff or revealed the plaintiff's confidential information. These suits may also be called "Jane Doe" or "Jean Doe" suits if it appears that the anonymous defendant is female. Once a party has filed a John Doe lawsuit, the rules of court procedure give the plaintiff tools to uncover the defendant's identity.

The most important of these tools is a subpoena: a legal order commanding the person or organization named in the subpoena to provide information or testimony at a specified time and place about a matter concerned in an investigation or a legal proceeding. In this type of case, the party issuing the subpoena usually demands that your Internet service provider (ISP), email provider, or web host produce documents or information that will reveal your identity.

You should be aware that sometimes plaintiffs file John Doe lawsuits against anonymous Internet users only to expose their identities, not because they want to pursue a legally valid claim against them.

There are technical precautions you can take to protect your anonymity, so that, even if someone issues a subpoena to your ISP, email provider, or web host, those sources will not have useful information about your identity. Please see the How to Maintain Your Anonymity Online section of this guide for details.

You also have the legal right to contest a subpoena seeking to reveal your identity. You usually do this by filing a "motion to quash" the subpoena, which is discussed below.

What happens when a subpoena to reveal your identity is issued depends a lot on whether you know about it. If you don't know about the subpoena, then you cannot challenge it in court, and your service provider may give up your identity without much of a fight. Luckily, the chances of you knowing about the subpoena are good (or at least they are getting better). If you find out about a subpoena demanding the disclosure of your identity, you should consider hiring a lawyer and moving to "quash" (i.e., challenge) the subpoena.

The hard reality is that there is no assurance that you will know when a subpoena is issued.

Nevertheless, it is becoming more and more common for service providers to notify their clients before responding to subpoenas that ask for identifying information. You might check with your ISP or e-mail service about its policy ahead of time. Some service providers have clauses in their terms of use or privacy policy stating that they make efforts to notify customers before responding to subpoenas of this kind. Please see the section entitled Getting Your Words and Other Content Out to the World for details on locating a web host or service provider that helps protect your anonymity. In the past, some ISPs have even taken it upon themselves to challenge subpoenas asking for identifying information about their clients.

Furthermore, courts in many states require that a plaintiff make reasonable efforts to notify the anonymous Internet speaker before obtaining disclosure of his or her identity. Unfortunately, this requirement only comes up if the plaintiff is required by state procedure to request permission from a court in order to issue the subpoena (which is often the case when a subpoena is issued very early in a lawsuit). The required efforts often including posting a notice about the subpoena on the website or message board where the complained-of statements appeared. Alternatively, the plaintiff may ask the service provider to send a notice to the anonymous poster (the ISP, email provider, or web host usually will have the email and/or physical address of the client, hence the reason for the subpoena in the first place).

Keep in mind, however, that neither of these practices is universal, and there is no guarantee that you will be notified before your identity is disclosed.

In general, judges do not review subpoenas as they are issued. Instead, you need to file a motion to block (or, in legal jargon, "quash") the subpoena.

The amount of time you have to file a motion to quash the subpoena is usually short -- typically around seven days -- so you need to move fast. You should ask your ISP or other provider for a copy of the subpoena, so that you can determine the court under whose authority the subpoena was issued. Assuming you want to challenge the subpoena, you should also contact a lawyer who can file a motion to quash with that court. Because of the generally short time limit for responding to subpoenas, your lawyer may need to file a request for an extension of time to file the motion.

In finding a lawyer to represent you, one option is to contact a local lawyer. Also, there are certain public interest groups, such as Public Citizen and the Electronic Frontier Foundation, that advocate for free speech online and might be interested in assisting you.

You may want to point your lawyer in the direction of the following cases, which are highly protective of Internet anonymity:

• Doe v. Cahill, 884 A.2d 451 (Del. 2005)
• Dendrite Int'l v. Doe, 775 A.2d 756 (N.J. App. Div. 2001)
• Mobilisa v. Doe, 170 P.3d 712 (Ariz. Ct. App. 2007)
• Independent Newspapers, Inc. v. Brodie, 966 A.2d 432 (Md. 2009)
• Solers, Inc. v. Doe, 977 A.2d 941, 954-57 (D.C. 2009)
• Krinsky v. Doe 6, 159 Cal.App. 4th 1154 (Cal. Ct. App. 2008)

You may also want to show your lawyer the following briefs for purposes of crafting legal arguments:

• Doe's appellate brief in Cahill
• Amicus brief in Cahill
• Doe's brief in Dendrite
• Amicus brief in Mobilisa
• Orthomom's brief in Greenbaum v. Google, 845 N.Y.S. 2d 695 (N.Y. Sup. Ct. 2007) .

For more information on the legal standards applied by courts before allowing a plaintiff to uncover an Internet speaker's identity, see the Legal Protections for Anonymous Speech section and your relevant state law section on anonymous speech in this guide.

Keep in mind that it might not always be worth it to challenge a subpoena seeking disclosure of your identity. It can be a costly process involving high legal fees, and there is no guarantee that hiring a lawyer will enable you to successfully challenge the subpoena. You should think carefully about whether your anonymity is worth the time and money required to protect it.

Because of these risks and costs associated with fighting a subpoena, you are better off taking steps to minimize the identifying information you provide about yourself if anonymomity is important to you. You'll find some useful information in this regard in the How to Maintain Your Anonymity Online section of the guide.

For more information on responding to subpoenas, see the section on Responding to Subpoenas in this guide. For information about defending against lawsuits generally, please see the Responding to Legal Threats section.