What is Spam ?

In email marketing, this refers to any message that is deemed by users or email providers to be an unsolicited commercial offer. Also called “junk mail.”
“Spam” may also refer to links or comments that are left on blogs, forums and message boards designed exclusively to steer users to a site for commercial gain. This kind of spam, generated by random visitors, is called “link spam” or “comment spam.”


In SEO, “spam” can be any Web page that a search engine views as harming the credibility of its results. Examples of these can include doorway pages, link farms, keyword stuffing, cloaking and other duplicitous or otherwise user-hostile practices. The standards for what constitutes SEO spam varies by search engine and current algorithm factors.

The classic definition of spam is unsolicited bulk messages, that is, messages sent to multiple recipients who did not ask for them. The problems caused by spam are due to the combination of the unsolicited and bulk aspects; the quantity of unwanted messages swamps messaging systems and drowns out the messages that recipients do want.

For practical and legal reason, different organizations have different definitions of spam. When a recipient gets a single message, it can be difficult to tell whether that message was part of a group sent in bulk, so a common alternative definition is unsolicited commercial e-mail, on the theory that most unwanted mail is commercial. Many mailbox providers consider it to be mail their users don’t want, or mail their users complain about, since their goal is to minimize the support costs associated with complaints. In practice these varying definitions describe approximately the same set of messages.


In countries that have laws related to spam, the most common legal definition is unsolicited commercial e-mail, along with mail that is misleading or fraudulent. The United States is an outlier; its CAN SPAM act only forbids commercial e-mail that is fraudulent or was sent after the recipient told the sender to stop. Non-commercial mail generally gets more lenient legal treatment than commercial mail.

Where It Appears

Spam has been a problem in many different media, and invariably arises whenever a medium allows people to send many messages without per-message charges. A short-lived flat-rate telegraph service in the 1800s closed due to spam in Morse code.

On the Internet, it has affected UseNet (the shared bulletin board system), e-mail, instant messaging, blogs and blog comments, and social media including Facebook and Twitter. It has also appeared as junk faxes, VoIP telephony, Instant Message (AOL Instant Message aka AIM, Apple iMessage, etcetera) and SMS (phone text messages.)

Spamming techniques have evolved as conditions have changed. For example, junk faxes were initially a local problem, as advertisers with new cheap fax machines used them to make free local calls, but high toll rates kept them from making long distance calls. Now, with toll rates in much of the world approaching zero, junk faxes are as likely to come from the other side of the world as from around the corner. On the Internet, as users have moved from one service to another, e.g., from GeoCities to MySpace to Facebook to Pinterest, spammers have followed them.


« Back to Glossary Index