Google has always been the master in Search Results and almost every webmaster in the world depends purely on the Google to get Visitors and valuable readers. However Google has also been implementing various algorithms to Fight against Spam in the following complete information graphics. While, in this process, Google itself has created lot of spam in the world. And Finally the Combination of both will make non-link relevancy signals which has altogether lowered the value of Organic Links from Search Engine.
Source: SEO Book
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