When we visit a website using our favorite browser, we usually just type in the basic part of the URL and 'arrive' at the desired location without any problems. But have we reached a point where we can start omitting 'www' from the URLs for all websites now, or is it still necessary to add it in?

Today’s Question & Answer session comes to us courtesy of SuperUser—a subdivision of Stack Exchange, a community-driven grouping of Q&A web sites.

The Question

SuperUser reader Celeritas wants to know if adding 'www' to website URLs makes a difference or not:

In modern web browsers, is there any point in putting 'www' in front of a website URL that uses it? When going to 'www.facebook.com' or 'www.cbc.ca', is there any benefit or difference made by omitting the 'www'?

Is it really necessary to add 'www' to website URLs now, or could you just omit it when browsing the internet and not experience any problems?

The Answer

SuperUser contributor Synetech has the answer for us:

It usually doesn’t, but it could.

This has nothing to do with the browser; it has to do with the web-server. The web-server is a computer (or even multiple computers) which receive queries for web-pages and send the appropriate data. A URL includes several parts, one of which is the name or address of the web-server.

Many companies host more than just a web-server, they may also run an FTP-server, a database-server, a mail-server, and so on. These could be hosted from the same machine as the web-server or on different machines.

In the past, it was common to specify the difference via a prefix for consistency. So for example, Acme Industries might buy the domain-name 'acme.org', then set up one or more computers to host the different services they have. When you want to use one of the services, you enter the appropriate host name:

So why does it still work without 'www'? Because most web-servers allow you to accept different URLs and redirect them as necessary. For the convenience of users, most companies and organizations set up a rule to have the web-server handle connections to the hostname on port 80 (the “web port”), or redirect it to another system if the web-server is a different machine.

Differentiating the service or machine being accessed can also be done through the port, but it requires specifically including it in the name, so it’s not really any better than using prefixes:

Sometimes the scheme can perform this function:

Using schemes works as well and can be done automatically using the appropriate software (e.g., a browser would add 'http://', an email client would add 'pop://', etc.). But there are not official schemes for every type of server that can exist, and inventing one is not ideal because it would require software to support it.

It’s becoming less and less necessary to include 'www', but it is not universal, and some sites still require it because it helps keep things organized.

Most of the time we can happily (and easily) omit typing in the 'www' portion of URLs for our favorite websites, but there is always a possibility you may encounter the 'rare' website that still requires it.

Have something to add to the explanation? Sound off in the comments. Want to read more answers from other tech-savvy Stack Exchange users? Check out the full discussion thread here.