From: http://womensissues.about.com/od/violenceagainstwomen/f/Cyberstalking.htm

Question: What is cyberstalking?

Answer: Cyberstalking is a technologically-based “attack” on one person who has been targeted specifically for that attack for reasons of anger, revenge or control. Cyberstalking can take many forms, including:

harassment, embarrassment and humiliation of the victim
emptying bank accounts or other economic control such as ruining the victim's credit score
harassing family, friends and employers to isolate the victim
scare tactics to instill fear and more.

The term can also apply to a “traditional” stalker who uses technology to trace and locate their victim and their movements more easily (e.g. using Facebook notifications to know what party they are attending).
A true cyberstalker’s intent is to harm their intended victim using the anonymity and untraceable distance of technology. In many situations, the victims never discover the identity of the cyberstalkers who hurt them, despite their lives being completely upended by the perpetrator.
Cyberstalking is not identity theft. An identity thief, whether stealing from a stranger or a family member, has a very specific goal in mind — financial gain. Identity thieves are unconcerned by the consequences of their behavior on the victim’s life, whereas the actions of a cyberstalker are deliberate and focused on the consequences to the victim.
The above piece is first in a series of nine articles on women and cyberstalking written for About.com by cyberstalking expert Alexis A. Moore, founder of the national advocacy group Survivors in Action. Links to the entire series are below.
Cyberstalking Article Index:

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Cyberstalking Laws:
http://www.ncsl.org/issues-research/telecom/cyberstalking-and-cyberharassment-laws.aspx

State Cyberstalking and Cyberharassment Law

Overview | State Statutes

Last update: Nov. 16, 2012
PLEASE NOTE: The National Conference of State Legislatures (NCSL) serves state legislators and their staff. This site provides comparative information only and should not be construed as legal advice. NCSL cannot provide assistance with individual cases.

Overview

Many states have enacted "cyberstalking" or "cyberharassment" laws or have laws that explicitly include electronic forms of communication within more traditional stalking or harassment laws. In addition, recent concerns about protecting minors from online bullying or harassment have led states to enact "cyberbullying" laws. This chart identifies only state laws that include specific references to electronic communication. However, other state laws may still apply to those who harass, threaten or bully others online, although specific language may make the laws easier to enforce. This chart classifies the various state laws addressing these three different types of online behaviors, as described below.
Cyberstalking. Cyberstalking is the use of the Internet, email or other electronic communications to stalk, and generally refers to a pattern of threatening or malicious behaviors. Cyberstalking may be considered the most dangerous of the three types of Internet harassment, based on a posing credible threat of harm. Sanctions range from misdemeanors to felonies.

Cyberharassment. Cyberharassment differs from cyberstalking in that it may generally be defined as not involving a credible threat. Cyberharassment usually pertains to threatening or harassing email messages, instant messages, or to blog entries or websites dedicated solely to tormenting an individual. Some states approach cyberharrassment by including language addressing electronic communications in general harassment statutes, while others have created stand-alone cyberharassment statutes.

* Note: This chart does not cover cyberbullying laws. Cyberbullying and cyberharassment are sometimes used interchangeably, but cyberbullying generally refers to electronic harassment or bullying among minors within a school context. See the NCSL's Education Program's cyberbullying page for more information on cyberbullyings laws and legislation.
See also: State laws related to electronic solicitation or luring of children, Internet filtering laws--schools and libraries, and NCSL LegisBrief: Protecting Children Online.

California
Cal. Civil Code § 1708.7, http://www.leginfo.ca.gov/cgi-bin/displaycode?section=civ&group=01001-02000&file=1708-1725

Cal Penal Code § 646.9 http://www.leginfo.ca.gov/cgi-bin/displaycode?section=pen&group=00001-01000&file=639-653.2

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