In general, extortion is the act of obtaining money or other property through some kind of force or threat. Threats may come in the form of violence, damage to property or reputation or even an adverse government act. In most cases, extortion falls into the larceny category of criminal acts rather than robbery. That's because the person initiating the extortion is usually not threatening immediate physical harm like a masked perpetrator with a gun would be.
In Washington, as in other states, extortion is a felony. One of the most common forms of extortion is blackmail, which usually involves the perpetrator threatening to make public information that might be embarrassing or otherwise damaging to another individual. Another common form of extortion is the "protection" scheme. In these scenarios, the perpetrator offers to "protect" small business owners from burglars and vandals that could potentially threaten the business after hours.