Difference Between www and Without www

Put it simple, domain name without www is the more authentic one. This is because HTTP does not specify your domain name must be started with www. or any other prefix. Indeed, www.yourdomain.com is just one of your subdomains.

Then why in early days every domain name starts with www? Well, it is just a common convention without much rationale, something like why at first place domain name on the Earth not like http:com.yourdomain.level-1-subdomain.level-2-sub/parameter-level-1/... We human being just sometimes make irrational stuff. So, early people name www.yourdomain.com as main domain and subdomain.yourdomain.com as subdomain, while technically they are all subdomains.

By now you would know www2., www3., www4. no longer a mystery. By now, most webmasters would have to make sure www.yourdomain.com being redirect to yourdomain.com.

Since www.yourdomain.com is just a subdomain of your main domain, it is no wonder search engines treat them as separate pages. This bad practice now is a norm to direct the yourdomain.com to www.yourdomain.com as part of getting your site SEO.

However, it is suggested to redirect www.yourdomain.com to yourdomain.com by include following code in your .htaccess file, which is located in public_html:

RewriteEngine On
RewriteBase /
RewriteCond %{HTTP_HOST} !^yourdomain.com [NC]
RewriteRule ^(.*)$ http://yourdomain.com/$1 [L,R=301]


http://www.seocompany.ca/seo/url-redirect.html
http://www.bluehostforum.com/showthread.php?t=1019