The confusion in this arises when Google or other SE's finally do penalize your domains for duplicate content. Right now everything could be hunky dory for you, but what happens when websites (usually takes quite a few of them) start linking to all those different domains? This can confuse the search engine and make it think there are two unique websites with dup content unless you have 301 redirects in place on all the secondary ones.
Why don't you set up 301 redirects on these spare or secondary domain to the main one?
Of course this is my opinion because I have see clients websites get in trouble like this before. I have seen the same issues with www and non-www domain as well.
|