Straight From Google - Deftly dealing with duplicate content

[Jace]

http://googlewebmastercentral.blogsp...e-content.html

During our crawling and when serving search results, we try hard to index and show pages with distinct information. This filtering means, for instance, that if your site has articles in "regular" and "printer" versions and neither set is blocked in robots.txt or via a noindex meta tag, we'll choose one version to list. In the rare cases in which we perceive that duplicate content may be shown with intent to manipulate our rankings and deceive our users, we'll also make appropriate adjustments in the indexing and ranking of the sites involved. However, we prefer to focus on filtering rather than ranking adjustments ... so in the vast majority of cases, the worst thing that'll befall webmasters is to see the "less desired" version of a page shown in our index.