Hi Charles,
Thanks for the reply. I'm fully aware about not having duplicate content on a site or material plagiarised from another site. That's not really what I'm talking about though.
As mentiioned at the start of the post my concern is about the fact any addon domain under your main account domain can be accessed by several urls therefore appearing to the search engines as though they are separate sites - which of course they are not - and therefore they will appear as having 100% duplicate content.
For example an addon domain
www.addondomain.com points to addondomain.mydomain.com
However, it can be accessed by several urls
-www.mydomain.com/addondomain
-mydomain.com/addondomain
-addondomain.mydomain.com
-www.addondomain.mydomain.com
-www.addondomain.com
-addondomain.com
I appreciate the replies of others on this post saying there is no risk of Google and other search engines seeing this as several sites and therefore duplicate content when spidering.
However I keep coming across more and more sites (several which are well respected) which say the contrary and warn of an addon domain will likely be penalised unless a .htaccess file is added to your site.
Comments I've come across on sites include: 'Having add-on domains does influence things from an Search Engine Optimization perspective as your add-on domain can be reached by different URL's. This means there are potential duplicate content issues when you're using add-on domains.'
'For those of you that make use of add-on domains on your hosting accoumt, its important to setup an .htaccess file to redirect any visitors or bots who find their way to one of the subdomains., to avoid duplicate content issues.'
There are dozens of sites discussing this matter and they all say it's important to takes to set up htaccess to avoid being penalised - You'll see what I mean if you look at any of the example links below:
Rankwell Blog Archive Htaccess for addon domains
Addon Domains - Solving duplicate content issue using .htaccess
Explanation about Addon Domain and using Modrewrite on it Reaper-X .:[ ID ]:.
Hosting multiple websites on one account - addon domains - 5 Star Affiliate Marketing Forums
(see bottom of page on this link)
Google Canonicalization Errors: The Dreaded Missing WWW Syndrome
Thanks
Wes