Cross Domain URL selection – When search engine find matching/identical content pieces on different URLs/websites, it runs an algorithm to select a primary URL among all other urls and removes them from search results.
What does this mean?
Google is laying emphasis on its algorithm to identify the original and highest quality link for the content, and to devalue the other URLs having same content, further removing them from the search results. The idea behind this is to cut down on duplicate search results and reduce a lot of copy cat, scrapers, and other unethical content websites. By doing this user will be benefited getting better and diversified search results, not just 10 different URLs saying the same thing.
What did Google say about it?
There are numerous possible causes of cross-domain URL selection which may include:
- detected duplicate content,
- 301 redirects,
- Configuration mistakes
- Incorrect canonicalization
- Misconfigured servers
- Malicious hacking
- Unauthorized copying
Having the same content available on more than one URL is an issue which is known as duplicate content. But when Google discovers a group of pages with duplicate content, it uses its algorithms to select one main URL for that content. That group of pages may contain URLs from the same site or from different sites. When one URL is selected from a group of different sites the selection is called a cross-domain URL selection.
For example, if the group of URLs contains one URL from a.com and one URL from b.com having same content, and Google’s algorithm select the URL from b.com, then the domain a.com may no longer be shown in the search results and may see a major drop in search traffic.
Messages in Google Webmaster Tools (GWT) (SEO perspective)
To inform the site owners about cross-domain URL selection happened, Google may send a message alert via GWT.
When GWT detects a cross-domain URL selection is affecting top pages of the website has occurred it may send the webmaster a message regarding it. However, when many URLs are affected by cross-domain URL selections, webmaster may not send any email or any message for the same URL multiple times.
These messages will be sent to the webmasters who have verified the ownership of their website in GWT. For receiving messages it is recommended to activate email delivery of GWT messages.