For this question we’ll paraphrase what we get asked almost daily by new clients, “How many domain names (web addresses) should I have for my site?”
The short answer is, “EXACTLY ONE”. If your one domain name has an obvious phonetic variation, then you might need a second domain (for example drjohnsmith.com and doctorjohnsmith.com).
Here’s the quick and dirty explanation of why multiple domains are bad:
Years back, some site owners bought and pointed multiple domains at their one website in an effort to get multiple search engine positions for the same pages. For a while it worked.
But the search engines realized that duplicate listings disappointed searchers and corrupted their results. In response, all of the major search engines now actively check for duplicate IP addresses, duplicate page code, and duplicate of content. On a good day, they just ignore all but one domain name. On a bad day they may reduce your rankings or remove your website altogether for attempting to manipulate results.
And even if the search engine didn’t catch on, you still risk reduced ranking. Link popularity, a major factor in today’s search ranking formulas, is DOMAIN NAME specific.
Consider this scenario, you and competitor each have ten legitimate inbound links. But your competitor has one domain and you have three. All of your competitor’s links point to his one domain name but your links are split between your various names. Because not one of your domains can match the number of links pointing at the competing domain, you are forever in the back of the search engine rankings pack.