Variety and Percentage of content changes in the document
The search engines measure historical and current percentage of change. They look for the amount of content that has changed in a document over the course of updates and which parts of the documents have experienced change over time.Â
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For example, cosmetic changes like color or fonts may be ignored, just like a template change. Search Engines like the document which keeps up with the changing times by adding new and updated content and removing the old content which has become outdated.Â
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Google has a patent on historic data, and the amount of change in a document may also be important.Â
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It also has impact on the keywords or key phrases of a document which is a good sign.