May 14, 2008
I have a client who has 2 domain names: namehere.com and differentnamehere.us pointing at the same IP address. Is it bad SEO to have multiple domain names for the same site? And will this negatively impact search engine results for each?
Two domains for one website is not in and of itself a bad thing. I have tons of domains for my one website. But problems can arise if your additional domain is simply a parked alias of your main domain and it somehow gets indexed by the search engines. Even this is not really a problem, but it's best to allow only your main domain to be indexed so as not to inadvertently trip any duplicate content filters.
You may already be doing this, but if not, what you want to do is set up a 301-permanent-redirect from the additional domain to your main domain. This will ensure that all visitors end up at the correct site, and that only your main domain gets indexed by the search engines. It will also help to pass to the main domain any link popularity that the additional domain may have accumulated.
Hope this helps!