Canonicalization is the process of picking the best url when there are several choices, and it usually refers to home pages. For example, most people would consider these the same urls: * www.example.com * example.com/ * www.example.com/index.html * example.com/home.asp please read Matt cutts blog for more details. http://www.mattcutts.com/blog/seo-advice-url-canonicalization/ You can solve this problem through Google Webmaster tools and also using tag. Read Google Webmaster Blog : http://googlewebmastercentral.blogspot.com/2009/02/specify-your-canonical.html