In the early days of the web, every site’s domain name was prepended with “www”. It’s nowhere near as common today — many sites choose to simply use the naked domain, but I’m often asked whether there is any particular reason to choose one option over the other. Is there any advantage to having “www” in your site’s domain?
The most common reason to discard “www” is for branding. The naked domain is snappy, looks better on promotional material, and most brands don’t want something as important as their domain name cluttered with unnecessary and unrelated letters.
What exactly is the “www”? Technically, it’s a subdomain traditionally used to indicate that a site is part of the web, as opposed to some other part of the Internet like Gopher or FTP. This isn’t strictly necessary, but it is traditional to include an indication of the services offered by a server in the domain, and Tim Berners-Lee used “www” for the first web pages at CERN.
There is nothing special about the “www” subdomain other than tradition. Any string of letters can be used in a subdomain. Take a look in the address bar of your browser as you read this article. It starts with “blog” because our blog lives on a subdomain of our primary nexcess.net domain. The main site lives on a “www” subdomain.
Let’s deal with the perennial myth that the choice makes a difference to SEO. It doesn’t. Google and the other search engines are just as happy to rank your site regardless of the presence of “www”.
For most bloggers and owners of relatively small sites, you can choose whether to use “www” or not, and it will have no impact.
That said, there are a couple of reasons that a site owner would choose to use the “www”. It’s not that “www” is special, but that there are benefits to using a subdomain rather than the naked domain — it could be any subdomain, but “www” is the obvious and traditional choice.
Let’s say you want to host static content on a separate subdomain to enhance the performance of your site. There is no need for cookies to be sent when static.mysite.com is loaded — it would be counter- productive. So, splitting the various parts of the site into subdomains makes for more efficient (and secure) cookie handling.
Domain Name System
The second most common reason to choose to use the “www” subdomain concerns DNS, the service that translates domain names into IP addresses that servers and routers understand.
Each domain name has several different record types. One of the most useful is the CNAME record. CNAME records don’t point to an IP; they point to another domain name. This is useful if you want an external service to be able to change where the domain points. If you’re using a content distribution network, the CDN vendor might want to point your domain at different servers, so they change the IP that their domain points to. You use the CNAME to point to their domain, and then you don’t have to worry about the specific IP — the CDN vendor handles that.
The problem with using the naked domain is that, while you can use a CNAME record on it, it is frowned upon because it will override other records you use on the domain. Using a CNAME with a naked domain is almost always a bad idea. There’s a more technical explanation of why this is so in section 3.6.2 of RFC 1034.
For owners of smaller sites, it doesn’t really matter whether you choose to use “www” or not. For larger sites that want to take advantage of flexible subdomain layouts, “www” can be a good idea.