There are three general types of magic words: * Behavior switches: these are uppercase words surrounded by double underscores, e.g. __FOO__. * Variables: these are uppercase words surrounded by double braces, e.g. {{FOO}}. As such, they look a lot like templates. * Parser functions: these take parameters and are either of the form {{foo:...}} or {{#foo:...}}. File:Blue Glass Arrow.svg See also: Help:Parser functions and mw:Help:Extension:ParserFunctions