I have two websites that mirror each other in content but utilize different keywords and meta tags. Will this help my chances for ranking or hurt them?
In no uncertain terms, building two websites that mirror each other in content will hurt your Internet marketing efforts. Google, Bing, AltaVista, AllTheWeb, Inktomi, and Yahoo! all explicitly state that you should not submit sites with mirrored content. Violating their rules is likely to get one or both of your sites permanently banned by the search engines.
If you have mirror sites, we suggest that you take down all but one of your websites.
For more information on how to best close down a website without losing the existing search engine links it already has, see Will changing our URL affect our search engine rankings? How can we change urls without losing the traffic we’re already getting?
What the search engines say about mirror sites and mirror pages:
“Don’t create multiple pages, subdomains, or domains with substantially duplicate content.”
On Google’s Spam Report page, “Duplicate site or pages” is specifically stated as a deceptive practice.
From: AltaVista – Help – FAQ – Adding & Removing URLs
“15. Are duplicate pages allowed in the index?
We work hard to detect and eliminate duplicate pages. If you spot duplicates, please let us know by reporting the duplicate pages via our Email form; please select ‘Spam Reporting’ in the Subject pull-down menu.”
AllTheWeb.com: About Us – Spam Policy
“Some examples of pages that exhibit ‘spam’ techniques are:… Pages, subdomains or domains that have substantially or very similar content.”
Inktomi – Content Guidelines
“What Inktomi Considers Unwanted…
Pages that have substantially the same content as other pages
Sites with numerous, unnecessary virtual hostnames…
Multiple sites offering the same content.”
To learn about other search engine optimization tricks that can get your website in trouble, read What is search spam, or SEO spam?.