Sitemap with References to Second Domain

[ShaMenz]

I have just discovered a client site that is serving content from a single database into two separate domains and has created xml sitemaps which contain references to both domains in an attempt to avoid being tagged for duplicate content.

I always thought that a sitemap was intended to show the files inside a single domain and the idea of multiple domains in the sitemap had never occurred to me...

The sites are both very large storefronts and one of them (the larger of the two) has recently seen a 50% drop in search traffic and loss of some 600 search terms from top 50 positions in Google. My first instinct is that the sitemaps should be altered to only show files within each domain, but am worried about causing further loss of traffic.

Is it possible that the inclusion URLs for the second domain in the sitemap may in fact be signalling duplicate content to Search Engines? Does anyone have a definitive view of whether these sitemaps are good, bad or irrelevant?

[Entrusteddev]

Hi, As far as I'm aware, a sitemap is exactly that, A site map, thus they shouldn't be used to map URLs for mulitple domains.

To avoid duplicate content canonical references should be used.

Use a separate site map for each domain.

[ShaMenz]

Hi Aran,

Thanks ... that is pretty much what I was thinking, just blew my mind when I saw it so wanted to check my reasoning.

The second domain is basically a part of the other site (which represents a niche), so I am thinking that those pages in the main site should reference the same pages in the niche site.

Your suggestion of using canonicals is slightly different from my initial solution - thought I should use 301 redirects so that juice is passed to the pages on the second domain. Is there a reason why you would use canonicals rather than 301's?

[dannypenrose]

Aran has pretty much hit the nail on the head, the main purpose of a sitemap from a SEO point of view is to submit it to Google Webmaster tools to help Google find all of the pages on your website. Of course sitemaps are also useful from a users point of view and helps people to quickly find a page on your site.

I would defiantly recommend you stick to one sitemap per domain.

Regarding redirects - these should help:

http://www.seomoz.org/blog/cross-domain-canonical-the-new-301-whiteboard-friday

http://www.seomoz.org/blog/301-redirect-or-relcanonical-which-one-should-you-use