So why do some websites require the "world wide web" prior to the relaxation from the address, while some appear to solve equally well using the "world wide web" as without them?

Can there be some compelling reason you'd setup your domain title to operate such as this?

You will find several reasons, here are a few:

1) The individual wanted it by doing this purposely

People use DNS for a lot of things, not just the net. They might require the primary dns reputation for another service that's more essential for them.

2) Misconfigured dns servers

If a person does a research of world wide web for your dns server, your DNS server will have to resolve it.

3) Misconfigured web servers

An internet server can host a variety of internet sites. It differentiates which site you would like through the Host header. You have to specify which host names you need to supply for the website.

4) Website optimisation

It is best not to handle both, but to forward one having a moved permanently http status code. This way the two addresses will not compete for inbound link ranks.

5) Snacks

To prevent issues with snacks not delivered back through the browser. This may also be solved using the moved permanently http status code.

6) Client side browser caching

Browsers might not cache a picture if one makes a request to world wide web and the other without. This may also be solved using the moved permanently http status code.

Some sites want it since the service is set up on that one established to deliver content through the world wide web sub-domain only.

This is as world wide web may be the conventional sub-domain for "InternetInch traffic. Just like port 80 may be the standard port. Clearly you will find other standard services and ports too (http tcp/ip on port 80 is certainly not special!)

Imagine mycompany...

mx1.mycompany.com 25 smtp, etc

ftp.mycompany.com 21 ftp

world wide web.mycompany.com 80 http

Sites that do not want it essentially have sending in dns or redirection of some-kind.

e.g.

*.mycompany.com 80 http

The onlty reason to get it done so far as I can tell is that if you want it and you need to.

There's no compelling reason, only lack of knowledge.

Individuals are simply mis-set up web servers.

To clarify comments: misconfigured as with needing the world wide web at the start and coming back error when utilized with no world wide web.