Duplicate Content Filter

To look for duplicate content as a result of site architecture, you can use a “site:www.example.com” query to examine the URLs of a web site that a search engine has indexed. All major search engines (Google, Yahoo!, Microsoft Live Search) support this feature. Usually this will reveal quickly if, for example, “printfriendly” pages are being indexed

Google frequently places content it perceives as duplicate content in the “supplemental index.” This is noted at the bottom of a search engine result with the phrase “supplemental result.” If your web site has many pages in the supplemental index, it may mean that those pages are considered duplicate content — at least by Google. Investigate several pages of URLs if possible, and look for the aforementioned cases. Look especially at the later pages of results. It is extremely easy to create duplicate content problems without realizing it, so viewing from the vantage point of a search engine may be useful.

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