Should you website domain url is:

http://world wide

in the event you setup an IIS site for

having a permanent redirect towards the world wide web address or just add the 2nd Url like a host header?

Should you where you can add the host header would affecting Search engine optimization?

I'd setup the world wide web subdomain to suggest to same position as no subdomain. This way the world wide web is entirely optional without any consequence for your customers.

The 2 addresses inside your example is going to be indexed individually even when they indicate the identical page. That redundant indexing will hurt you as search engine results is going to be split between two valid results. Mitigate all individuals problems by utilization of a canonical link tag.

<link rel="canonical" href="" type="text/html"/>

The kind attribute is really a valid attribute on all link tags, but so far as Yes, it isn't based on search engines like google at this time around. I throw it inside as It will probably assist indexing later on if this involves aiding searching bot seem sensible from the page after initial analysis.