URL Canonicalization

“Canonicalization” - The process of picking the best url when there are different choices, and it usually refers to the homepage.

Search engines would consider these urls as same:

* example.com
* example.com/
* example.com/index.html
* example.com/home.asp
* e.t.c.

In other words, the search engines may consider such pages as duplicated and ignored them when it comes to indexing and may ignore them.

If you server supports the use of an .htaccess file and your hosting provider allows you to edit it, here is an example what to edit:

### Require the www to avoid cannonicalization issues ###
RewriteCond %{HTTP_HOST} ^seoworkers.com [NC]
RewriteRule ^(.*)$ http://www.seoworkers.com/$1 [L,R=301]

### Require the slash to avoid cannonicalization issues ###
RewriteCond %{HTTP_HOST} !^www\.seoworkers\.com [NC]
RewriteRule ^(.*)$ http://www.seoworkers.com/$1 [L,R=301]

### Redirect index.html to / ######
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*index\.htm?\ HTTP/
RewriteRule ^(.*)index\.htm?$ http://www.seoworkers.com/$1 [R=301,L]

### Redirect index.php to / ######
RewriteCond %{THE_REQUEST} ^[A-Z]{3,9}\ /.*index\.php?\ HTTP/
RewriteRule ^(.*)index\.php?$ http://www.seoworkers.com/$1 [R=301,L]

If you are not hosting on an Apache server or your server does not support .htaccess files, here are some additional server side scripting solutions: Search Engine Friendly Permanent Redirects

More about this, you can read the post of Matt Cutts, Principal Software Engineer at Google SEO advice: url canonicalization.