photo credit: meneame comunicacions, sl

A largely missed concept with webmasters is how to use 301 redirects.   They are the only safe SEO redirect.

With regards to SEO and the duplicate content penalty, you should redirect all non www requests on your domain to www unless there is a special case where this is required for site functionality.   This means…

http://tdcreative.net is 301′ed to http://www.tdcreative.net
http://tdcreative.net/my-post is 301′ed to http://www.tdcreative.net/my-post

Any person involved with SEO should know this and it can be achieved with a few lines of .htaccess code placed in the public root of your FTP, sometimes public_html or httpdocs.  An example….

Options +FollowSymlinks
RewriteEngine on
rewritecond %{http_host} ^your-domain.com [nc]
rewriterule ^(.*)$ http://www.your-domain.com/$1 [r=301,nc]

Simply add this code to the top of your .htaccess file.

Very simple, very effective.