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Since about 5 years out site was launched as "www.example.com" but last June 2012, we relaunched new design but somehow went without www subdmain - "http://example.com". We didn't check that time but now find duplicate pages and very confused what next.  Please answer: Do search engines penalize for the change of domain name? www.example.com vs example.com? How can go back (or, should we really?) to www.example.com? I did redirect .htaccess rewrite from nonwww to www - but now our site is launched as without www. Confused so Please advise ASAP. Thanks a Million