Email spam

Email spam, also referred to as junk email, spam mail, or simply spam, refers to unsolicited messages sent in bulk via email. The term originates from a Monty Python sketch, where the name of a canned meat product, "Spam," is used repetitively, mirroring the intrusive nature of unwanted emails.^[1] Since the early 1990s, spam has grown significantly, with estimates suggesting that by 2014, it comprised around 90% of all global email traffic.^[2][3]

Spam is primarily a financial burden for the recipient, who may be required to manage, filter, or delete these unwanted messages. Since the expense of spam is mostly borne by the recipient,^[4] it is effectively a form of "postage due" advertising,^[5] where the recipient bears the cost of unsolicited messages. This cost imposed on recipients, without compensation from the sender, makes spam an example of a "negative externality" (a side effect of an activity that affects others who are not involved in the decision).^[6]

The legal definition and status of spam varies from one jurisdiction to another, but laws and lawsuits have not generally been successful in stemming spam.^[7]

Most email spam messages are commercial in nature. Whether commercial or not, many are not only annoying as a form of attention theft, but also dangerous because they may contain links that lead to phishing web sites or sites that are hosting malware or include malware as file attachments.

Spammers collect email addresses from chat rooms, websites, customer lists, newsgroups, and viruses that harvest users' address books. These collected email addresses are sometimes also sold to other spammers.