SLAPP = Strategic Lawsuit Against Public Participation
Lawsuits targeting individuals who post anonymously on the Internet, usually because their posted messages criticize the actions of public figures or corporations, are sometimes called cyberSLAPPs. Like a regular SLAPP, a cyberSLAPP aims at chilling free speech by intimidating critics with the prospect of defending an expensive lawsuit. But it also often aims at uncovering the identity of the anonymous critic.
Most SLAPPs ultimately would fail if litigated fully, but the SLAPP filer doesn’t usually intend to do so. The point of a SLAPP is to intimidate and silence the target through the threat of an expensive lawsuit.
Although the First Amendment to the U.S. Constitution protects freedom of speech, the U.S. legal system generally gives the benefit of the doubt to a party bringing a lawsuit until the fact-finding stage, and a winning defendant is not usually entitled to recover attorneys’ fees to cover the expense of legal defense (as in some other countries). This means that, even if the claim ultimately fails, the process of defending against a SLAPP through the legal system can be a daunting and expensive prospect for many individuals.
To guard against the chilling effect of SLAPPs, the state of California has enacted anti-SLAPP legislation.
You can use California’s anti-SLAPP statute to counter a SLAPP suit filed against you.
The statute allows you to file a special motion to strike a complaint filed against you based on an “act in furtherance of [your] right of petition or free speech under the United States or California Constitution in connection with a public issue.” Cal. Civ. Proc. Code § 425.16.
If a court rules in your favor, it will dismiss the plaintiff’s case early in the litigation and award you attorneys’ fees and court costs.
In addition, if a party to a SLAPP suit seeks your personal identifying information, California law allows you to make a motion to quash the discovery order, request, or subpoena.
http://www.dmlp.org/legal-guide/responding-strategic-lawsuits-against-public-participation-slapps
http://www.dmlp.org/legal-guide/anti-slapp-law-california