That presumes there is a dilutive effect when both the component words and the string are indexed for a page. I have never encountered any such effect. However, when the words are part_of_a_sentence, for example, the URL can be seen to convey meaning unto the page, beyond the literal words it contains.
For example, if I named a file a_plague_o_both_your_Houses.html, I wouldn't have to tell the spider this page has something to do with Shakespeare --
