Many webmasters have a misconception that www is a subdomain, Actually www is a hostname. For SEO perspective, there is no difference between www and non-www. you can use any version of your domain. But there are many Technical benefits of using www version of the domain.
WWW vs non-WWW – Which is Better For WordPress SEO?
Why using WWW
Ability to restrict cookies: www has an ability to restrict the cookie when using subdomains. For speed up your WordPress site, there is necessary to serve static content from cookieless subdomain. If you are using naked domain cookies sent to all of your subdomains which cause the slowing website. If you are using www then your site’s cookies won’t be sent to the subdomain.
Flexibility with DNS: www gives a more flexibility with DNS. For effective use of CDN and cloud hosting, It is necessary to use www hostname with your domain because If you are running big site and want to use CDN for serving static content, you are to set up the DNS record for your site as a CNAME to some cdn.com address. It gives the CDN the opportunity to supply an IP address that is close to the user browser. You can’t set a cname record on a naked domain. In DNS, A records can only point to an IP address, hence you are pointing your bare domain at one and only ever one machine. If you used an A record on your site, then you would not be able to offer this flexibility. Using of www gives you the opportunity to use a CNAME for www that points to your CDN without changing the NS and SOA records.
So there is not a specific benefits of using naked domain. Today you are running a new or small website but in the future when your website will have a lot of traffic www gives you more flexibility and benefits for using CDN, Cloud hosting and control the site’s cookies.
Need to add or remove www
If your site new and yet launching we suggest you to use www instead of non-www. But if your site old and have traffic stick with your choice. It will make your website appear more consistent to search engines and to your users. If you are using Google Webmaster Tools it gives you the opportunity to set your preferred domain which you want to index with google www or non-www. If you don’t set the preferred domain Google treats the www and non-www versions of the domain as separate pages.
Choosing one does not impact your site SEO but you should specify a canonical URL for the sake of SEO and duplicate content issues by putting a “rel=canonical” tag in the <head> section.
<link rel="canonical" href="http://www.mydomain.com/blog" />
After choosing one domain option. you should redirect the other by 301 redirect. If you prefer naked domains, redirect to it when a visitor requests the www version.
RewriteEngine on
RewriteCond %{HTTP_HOST} !^mydomain.com [NC]
RewriteRule ^/?(.*)$ http://mydomain.com/$1 [L,R=301]
In WordPress, there is no need to setting up 301 redirection. You can set your preferred URL with or without www from WordPress General Setting. Others will redirect automatically.
So we hope this article helps you to understand the difference between www and non-www URL. Both are same SEO benefits but www gives you technically benefits when your site grows.