The examples and perspective in this article deal primarily with the English-speaking world and do not represent a worldwide view of the subject. (August 2019) (Learn how and when to remove this template message)
Extortion (also called shakedown, outwrestling and exaction) is a criminal offense that consists in the obtainment of money, property, or services from an individual or institution, through coercion. It is sometimes euphemistically referred to as a "protection racket" since the racketeers often phrase their demands as payment for "protection" from (real or hypothetical) threats from unspecified other parties; though often, and almost always, such "protection" is simply abstinence of harm from the same party, and such is implied in the "protection" offer. Extortion is commonly practiced by organized crime groups.  Exaction refers not only to extortion or the demanding and obtaining of something through force, but additionally, in its formal definition, means the infliction of something such as pain and suffering or making somebody endure something unpleasant.
The term extortion is often used metaphorically to refer to usury or to price-gouging, though neither is legally considered extortion. It is also often used loosely to refer to everyday situations where one person feels indebted against their will, to another, in order to receive an essential service or avoid legal consequences. 
In law, the word extortion can refer to political corruption, such as selling one's office or influence peddling, but in general vocabulary the word usually first brings to mind blackmail or protection rackets. The logical connection between the corruption sense of the word and the other senses is that to demand bribes in one's official capacity is blackmail or racketeering in essence (that is, "you need access to this resource, the government restricts access to it through my office, and I will charge you unfairly and unlawfully for such access").
Extortion is distinguished from robbery. In robbery, whether armed or not, the offender takes property from the victim by the immediate use of force or fear that force will be immediately used (as in the classic line, "Your money or your life"). Extortion, which is not limited to the taking of property, involves the verbal or written instillation of fear that something will happen to the victim if they do not comply with the extortionist's will. Another key distinction is that extortion always involves a verbal or written threat, whereas robbery does not. In United States federal law, extortion can be committed with or without the use of force and with or without the use of a weapon.
In blackmail, which always involves extortion, the extortionist threatens to reveal information about a victim or their family members that is potentially embarrassing, socially damaging, or incriminating unless a demand for money, property, or services is met.
In the United States, extortion may also be committed as a federal crime across a computer system, phone, by mail, or in using any instrument of interstate commerce. Extortion requires that the individual sent the message willingly and knowingly as elements of the crime. The message only has to be sent (but does not have to reach the intended recipient) to commit the crime of extortion.
In England and Wales extorting property and money by coercion is the offence of Blackmail which covers any "unwarranted demand with menaces" including physical threats. See section 21 of the Theft Act 1968 plus sections 29 and 30 of the Larceny Act 1916. A group of people may also be committing conspiracy.
Extortion is a common law offence in Scotland of using threat of harm to demand money, property or some advantage from another person. It does not matter whether the demand itself is legitimate (such as for money owed) as the offence can still be committed when illegitimate threats of harm are used.
Cyberextortion is when an individual or group uses the internet as an offensive force. The group or individual usually sends a company a threatening email stating that they have received confidential information about their company and will exploit a security leak or launch an attack that will harm the company's network. The message sent through the email usually demands money in exchange for the prevention of the attack.
In March 2008, Anthony Digati was arrested on federal charges of extortion through interstate communication. Digati put $50,000 into a variable life insurance policy by New York Life Insurance Company and wanted a return of $198,303.88. When the firm didn't comply, he threatened to send out 6 million spam emails. He registered a domain in February 2008 that contained New York Life's name in the URL to display false public statements about the company and increased his demand to $3 million. According to prosecutors, Digati's intent was not to inform or educate but he wanted to "damage the reputation of New York Life and cost the company millions of dollars in revenue,". New York Life contacted the Federal Bureau of Investigation and Digati was apprehended.
On February 15, 2011, Spanish police apprehended a man who attempted to blackmail Nintendo over customer information he had stolen. The man stole personal information about 4,000 users and emailed Nintendo Ibérica, Nintendo's Spanish division, and accused the company of data negligence. He threatened the company that he would make the information public and complain to the Spanish Data Agency if his demands were not met. After Nintendo ignored his demands, he published some of the information on an Internet forum. Nintendo notified authorities and the man was arrested in Málaga. No information has been revealed as to what the man demanded from Nintendo.
On February 7, 2019, Jeffrey P. Bezos, owner of Amazon and The Washington Post and currently the world's wealthiest person, accused the National Enquirer and its parent company American Media, Inc., of attempting to extort him by threatening to reveal nude pictures of him unless he publicly stated that he "[has] no knowledge or basis for suggesting that AMI's coverage was politically motivated or influenced by political forces." This threat was in response to Bezos investigating the tabloid for publishing details about his relationship with Lauren Sanchez, which led to Bezos and his wife Mackenzie announcing their divorce on January 9 of that year. Bezos refused and posted the threat on Medium.