Importance of urls in ranking

[varun1182]

Urls affect Google rankings as directory names and filenames are very important to Google.
Here's how Google sees files on a server... the most important page is the homepage at the root. .Next are the directory and subdirectory homepages (up to 2 deep). Next are the files on the root named something other than what is thrown up by default.

Even your file name extension has importance. An older study also has .shtml rank highest, then .shtm, html and htm in that order for straight web pages. .php actually ranks best for dynamic pages, then .asp.

So here is a list of possibilities in the order that they might rank best:

server.com/index.php
server.com/default.php
server.com/home.php
server.com/index.asp
server.com/default.asp
server.com/home.asp
server.com/index.shtml
server.com/default.shtml
server.com/home.shtml
server.com/index.shtm
server.com/default.shtm
server.com/home.shtm
server.com/index.html
server.com/default.html
server.com/home.html
server.com/index.htm
server.com/default.htm
server.com/home.htm
server.com/keyword/index.php
server.com/keyword/default.php
server.com/keyword/home.php
server.com/keyword/index.shtml
server.com/keyword/default.shtml
server.com/keyword/home.shtml
server.com/keyword/index.shtm
server.com/keyword/default.shtm
server.com/keyword/home.shtm
server.com/keyword/index.html
server.com/keyword/default.html
server.com/keyword/home.html
server.com/keyword/index.htm
server.com/keyword/default.htm
server.com/keyword/home.htm
server.com/keyword/keyword2/index.php
server.com/keyword/keyword2/default.php
server.com/keyword/keyword2/home.php
server.com/keyword/keyword2/index.shtml
server.com/keyword/keyword2/default.shtml
server.com/keyword/keyword2/home.shtml
server.com/keyword/keyword2/index.shtm
server.com/keyword/keyword2/default.shtm
server.com/keyword/keyword2/home.shtm
server.com/keyword/keyword2/index.html
server.com/keyword/keyword2/default.html
server.com/keyword/keyword2/home.html
server.com/keyword/keyword2/index.htm
server.com/keyword/keyword2/default.htm
server.com/keyword/keyword2/home.htm
server.com/keyword-keywords.php
server.com/keyword-keywords.shtml
server.com/keyword-keywords.shtm
server.com/keyword-keywords.html
server.com/keyword-keywords.htm

While reading for search engine optimization, I came across this interesting example.
Any views??