If you try and go to our website without typing the www. You get a page not found error. In my case it goes to a Yahoo 404 page where the website you typed is not even shown in the search results.
My question is how important is it that customers cannot type this manually? I guess that google etc will just spider the www version and so it will show in the search results in the same manner. Also what is the reason why some websites can be found without the www and some not?
It matters. Every site should resolve with and without the 'www' because:
Your 'marketing people' should pick either 'www.example.com' or 'example.com' and redirect the other version accordingly. They might like to read the advice here to decide if they want the 'www' or not: When should I use a www subdomain?
To get the 'www' part working, they might have to add an 'A' record for the 'www' subdomain to the site's DNS records. The process differs slightly with different domain registrars, so you should tell them to contact the company they purchased the domain from to ask for help setting up the 'www' subdomain to point to the main site. (Many registrars have help pages that talk you through it.)
Redirecting the 'www' version to the non-www version (or vice-versa) differs slightly depending upon what server the website is hosted on. One of the most common servers is called Apache, and they can follow the advice listed on this post to automatically redirect visitors from one version of the domain to the other.
Finally, they should also sign up to use Google Webmaster Tools and set the preferred domain that appears in Google search results to include or omit the 'www'.
If a website doesn't work without the www then I try it with, and some browsers automatically retry with a www if it fails without. If every link that points to your site uses the www then search engine spiders will find it.
However I think it looks unprofessional if it doesn't work without. The reason for using the www goes back to the beginnings of the internet when you had your ftp server at ftp.example.com and your www server at www.example.com (and other things now gone). I guess the www started being dropped for reasons of space on advertising and so people didn't have to type so much. It's never been needed at all.
You could have a website where example.com and www.example.com are completely different websites, but that would confuse people so you never see it.
Although you don't ask it, the way to get your site to work with and without is to use redirects so that it works both ways. What sort of server have you got?
The easiest fix for this is to have a CNAME record added to the DNS...
mycompany.com CNAME www.mycompany.com
www.mycompany.com A xxx.xxx.xxx.xxx
In the above, the A record means www.mycompany.com resolves directly to the IP address xxx.xxx.xxx.xxx and the CNAME record means mycompany.com is an 'alias' for www.mycompany.com
If you do it this way then if the IP address for www.mycompany.com is ever changed, the CNAME will still remain valid.
You'd be quite foolish to make the same website available via website.com and www.website.com as this will seriously affect your search engine rankings as it would be classed as split content.
As far as I'm concerned, the best way to do it is either have only the www.website.com resolve or if you really must use the website.com, have 301 redirects set up to point to the www.
In your case you probably should use the 301 redirects the other way around.
Making website.com available in that way also opens up a new can of worms when considering * records in your dns records as well.
