Spam
Spam is a term for any unsolicited bulk message. Spam is usually junk email, but it can also take the form of text messages, phone calls, or social media messages. Many email services include an automatic spam filter that detects spam and sends it to a junk folder instead of the inbox.
The goal of spam is ultimately to get someone to open a message and entice them to buy a product or service, which may or may not be a fraud. Some spammers instead try to trick users into infecting their computers with a virus to steal valuable information or extort money from the victim. Spammers also send bulk emails to conduct phishing scams.
Spam filters attempt to identify and block spam by analyzing a message's content and metadata. The most basic filters will look for certain trigger words in an email. A link to a website used in previous spam emails can also cause a message to get marked as spam. Frequent spammers will also be blacklisted by their IP addresses to prevent them from reaching inboxes.
History of the Term
The term comes from the Hormel canned meat product and a 1970 sketch on the Monty Python television show. In the sketch, the word is said more than 130 times in 3½ minutes, which inspired some early Internet users to repeatedly post the word "spam" to newsgroup message boards and drown out any other discussion. This unproductive exercise was termed "spamming." Once unsolicited bulk commercial messages started being posted to newsgroups and arriving in email inboxes, Internet users applied the term to that practice as well.