Descriptive File and folder names are a great idea, both for the robot viewer and for the human being, for the searcher, google for example lists websites and on the last line lists the URL of the page, A viewer would be tempted to visit a well structured URL that confirms with what he is looking for, For example if he is looking for information on how to install a new air manifold for a fiat car, he would be tempted by a url like
http://www.a-car-site-name.com/mechanics/fiat/manifold 
Now for the search engine, those file names could work as keywords (no evidence of this but it is very probable).