"The clacks in Terry Pratchett's Discworld novels is a network of semaphore towers stretching along the Sto Plains, into the Ramtops and across the Unnamed Continent to Genua. It was introduced in The Fifth Elephant and has become the Discworld's first network telecommunications network. While the system structure is that of a telegraph, elements of it are often described as similar to the Internet; for example, it threatens to make the Post Office obsolete in Going Postal (which also features a group of clacks hackers) and is sometimes described as 'c-mail' (a clear reference to email). 'C-commerce' is also carried out on it. A possible influence for the clacks system is the similar semaphore network in the Roberts Keith Roberts novel (novel) Pavane or the hoodwinker towers in Blue World (novel) The Blue World by Vance Jack Vance. Both are based on the real-world telegraph optical telegraphs used in the early 19th century before electrical telegraphy made them obsolete. A similar telegraph system is described in the Sprague de Camp L. Sprague de Camp novel Darkness Fall Lest Darkness Fall. The name itself may have been inspired by 'clackers', the term for operators of mechanical computers in William Gibson and Sterling Bruce Sterling's steampunk novel Difference Engine The Difference Engine; it is also a play on the word 'fax'."@en . . . "Clacks"@en . . "The clacks in Terry Pratchett's Discworld novels is a network of semaphore towers stretching along the Sto Plains, into the Ramtops and across the Unnamed Continent to Genua. It was introduced in The Fifth Elephant and has become the Discworld's first network telecommunications network. While the system structure is that of a telegraph, elements of it are often described as similar to the Internet; for example, it threatens to make the Post Office obsolete in Going Postal (which also features a group of clacks hackers) and is sometimes described as 'c-mail' (a clear reference to email). 'C-commerce' is also carried out on it."@en .