Why does the redirect question even have to arise in the first place? There are 2 main reasons:
1. To make sure all users can access your webpage
Some users will type in example.com in the address bar. Others will type www.example.com. A few will also do http://example.com or http://www.example.com.
You want all of them to point to the correct version of our web address; it would be sad (stupid?) to lose traffic just because someone omitted the www or added an extra one.
2. To funnel all link juice to your real website
Just like different people will access your website using different URLs, different people will link to your website in the same fashion. With WWW or without it.
You don’t want to have your inbound link strength divided among two ‘different’ websites (or even worse, lose the link strength altogether because one version is not even available!).
Redirecting to the correct version of your website makes sure inbound links don’t go waste, regardless of the version of the URL people use to link to you.
Now that we’ve established the ‘why’, let’s get into which version of the URL to use.
“Should I make my website a WWW one or a non-WWW one?”
The web is filled with arguments (and web wars) for both sides. There are even entire websites dedicated to promoting the use of each version.
For WWW: http://www.yes-www.org
For non-WWW: http://no-www.org
I will distill down the main arguments for both and will list them in this article.
Arguments for Using WWW
The main benefit of using WWW is the ability to use CDNs like the free Cloudflare service. CDNs cache static content and make them available geographically nearer to Internet users. This greatly increases page load speed (and decreases page load time, which is a big plus for user experience and SEO).
You will not be able to use a CDN on example.com, but it’s a 30-second operation if your website is www.example.com.
The technical explanations are here if anyone is interested.
Other arguments include cookie restriction and a reminder that the World Wide Web is not THE Internet, but part of it.
Arguments for Ditching WWW
It’s shorter. That’s really about it. example.com looks better in advertising and sounds better when speaking. Saying www.example.com is so 90s. Non-WWW addresses are modern, like Twitter.com.