Has MSN ever considered allowing webmasters to specify the default domain name for their authenticated sites, specifically designating whether the site is http://www.example.com or http://example.com in order to reduce the duplicate listings of identical pages?
The above can be accomplished by using a 301 redirect, which is generally considered the best solution. However, 301 redirects are generally not available for websites in shared hosting environments, which means millions of websites have duplicate content for their www and non-www pages.
Google allows webmasters to set a preferred domain (either www or non-www), with the preferred domain shown in the search results and all backlinks (whether www or non-www) are pointed to the preferred domain. The following schedule shows the effect of being able to select a preferred domain for Google versus Yahoo and MSN which do not offer this option:
Actual pages in sitemap: 457
Pages indexed by Google: 454
Pages indexed by Yahoo: 847
Pages indexed by MSN: 2,500
All of the above search engines have the same sitemap and the site is authenticated with all of them also, with the above figures coming straight from each search engine's webmaster tools section.