someplace between 25% to 30% of the material on the web is duplicative. Of all the web pages and material throughout the web, over one-quarter of it is repeated or duplicative.But Cutts says you
do not have to fret about it. Google doesn’t treat duplicate material as spam. It is true that Google just wishes to show one of those pages in their search results page, which might seem like a penalty if your material is not chosen– but it is not.Google takes all the duplicates and groups them into a cluster.
Then Google will reveal the very best of the lead to that cluster.Matt Cutts did say Google does reserve the right to penalize a website that is excessively replicating content, in a manipulative way. But in general, duplicate material is normal and not spam.Here is the video: