My "other" host runs cPanel, so I thought I'd explain what it's like so others here can see where the OP's ideas are coming from.

Let's say you sign up for a cPanel host for the domain examplesite.tld. The home directory on my cPanel host would be /home/examples/. That's the first 8 characters of the domain name. These first 8 characters of your initial domain name also doubles as your username.

The web root for examplesite.tld on the cPanel host would be:

/home/examples/public_html/

If you added hosting for another domain, say anothersite.tld, the web root for that on the cPanel host would be:

/home/examples/public_html/anothersite/

If you added hosting for a subdomain, say subdomain.examplesite.tld, the web root for that on the cPanel host would be:

/home/examples/public_html/subdomain/

In reply to:

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4. Is there a 'primary' domain associated with your site? ie one that everything else depends on existing?

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In reply to:

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I have manage a number of CPanel accounts that have 'addon' and 'parked' domains that operate as sub-domains of a primary domain. I'm interested to know how DreamHost's 'unlimited domains' works in comparison to this.

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In contrast to the above, which is my understanding of how my cPanel account works, the following are the web directories here at Dreamhost:

/home/username/examplessite.tld/
/home/username/anothersite.tld/
/home/username/subdomain.examplesite.tld/

So there's nothing special with the first domain you host vs the subsequent ones.

My example here has used the case where you've chosen to use the same unix username for each of your domains and subdomains. As other responsders in this thread have mentioned, you don't need to do this. You could just as easily have had your three sites use three different users or have two under one and one on its own, etc.

Have you thought of that additional question?

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