[peter_d]

Google's Vanessa Fox outlines issues concerning duplicate content:

Google wants to serve up unique results and does a great job of picking a version of your content to show if your sites includes duplication. If you don't want to worry about sorting through duplication on your site, you can let us worry about it instead.
Duplicate content doesn't cause your site to be penalized. If duplicate pages are detected, one version will be returned in the search results to ensure variety for searchers.
Duplicate content doesn't cause your site to be placed in the supplemental index. Duplication may indirectly influence this however, if links to your pages are split among the various versions, causing lower per-page PageRank.

http://googlewebmastercentral.blogsp...it-at-smx.html