To set your domain in google, go to the www.google.com/webmasters/tools/ website and set your preferred domain.
After you set the preferred domain, you should force everyone to use this domain with a 301 redirect. You do this by editing your root .htaccess file, if hosted on a Linux server. If you do not have a .htaccess file you will need to create one first as follows:
1) Create a text file and name it .htaccess
2) Modify it with the preferred domain code (as details below)
3) Upload it to the root of your server (public www)
If you want people to redirect from non-WWW to WWW:
(for example, if someone types in http://yourdomain.com, it will forward to http://www.yourdomain.com)
RewriteEngine On
RewriteCond %{HTTP_HOST} !^(.*)\.yourdomain\.com$ [NC]
RewriteRule ^(.*)$ http://www.yourdomain.com/$1 [R=301,L]
If you want people to redirect from WWW to non-WWW:
(for example, if someone types in http://www.yourdomain.com, it will forward to http://yourdomain.com)
RewriteEngine On
RewriteCond %{HTTP_HOST} ^www\.yourdomain\.com$ [NC]
RewriteRule ^.*$ http://yourdomain.com%{REQUEST_URI} [R=301,L]
Don't forget to replace “yourdomain” with the URL of your domain, otherwise the code above won't work!
Therefore by setting a preferred domain you are ensuring that Google and all the major search engines will only index your url web links from one domain. This will help your PageRank in search engine rankings.
So don't put it off, set your preferred domain, if you have not done so already! You will see your PageRank rise!
