Leecher (computing)

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In computing and specifically in Internet slang, a leech is one who benefits, usually deliberately, from others' information or effort but does not offer anything in return, or makes only token offerings in an attempt to avoid being called a leech. In economics, this type of behavior is called "free riding" and is associated with the free rider problem. The term originated in the bulletin board system era, when it referred to users that would download files and upload nothing in return.

Depending on context, leeching does not necessarily refer to illegal use of computer resources, but often instead to greedy use according to etiquette: to wit, using too much of what is freely given without contributing a reasonable amount back to the community that provides it. The word is also used without any pejorative connotations,^[1][2] simply meaning to download large sets of information: for example the Usenet newsreader NewsLeecher.

The name derives from the leech, an animal that sucks blood and then tries to leave unnoticed. Other terms are used, such as "freeloader", "mooch" and "sponge", but leech is the most commonly used.