Urls are important to search engines because they should express the primary purpose of the page. Unlike meta keywords, it is very difficult to keyword-stuff a

Urls are important to search engines because they should express the primary purpose of the page. Unlike meta keywords, it is very difficult to keyword-stuff a URL, because search engines can detect duplicate content. So a person needs to select the URL for a page that best describes that page, which increases the search signal quality for a URL. Urls are important to humans for the same reason we save documents with meaningful names instead of random gibberish. Urls are the way people use sites, and that's just the way it is.