If you read Tolkien's books you most likely will recognize the title of this blog post. It's about power. Absolute power. If you aim for high impact communication on the overloaded Internet, you better avoid being sandboxed by search engines because of duplicate links to essentially the same content. In addition, you don't want to confuse your audience in a spaghetti of URLs. Finally, duplication is hard to maintain anyway.
Fortunately there's a simple yet effective solution: the Global Redirect module.