Now this is not a mysterious key to everyone. The sign is often included on a Mac keyboard, though PC keyboards i have and use do not seem to have it. Not all typewriters have this sign either, but what is it? The section sign is used to reference individually numbered section or paragraphs of a document, often used with legal documents. Thus a reference to section 6 in a document may be written as §6. Double it up if you want to refer to multiple sections, for example §§2-5 means sections 2 through 5.
Below is the section sign on my Triumph-Adler Tippa.
