Hi, I have an issue with my bans store where google is picking up the pages twice, once with the www. and another time without it. I can see this with the site:domain.com search in google. I believe this is creating a duplicate content penalty and making the pages hit the supplamental results more easily. Any one else found this? Any advice to get around this? This could be a big part of why some people believe these sites are hard to SEO.
sign up for google webmaster tools then go to tools > Set preferred domain then you can set which one you prefer in there.
Does your host use Apache? You could force or redirect all visitors to www using .htaccess. .htaccess tutoral