There are two forms of penalties by Google: Algorithmic and Manual. And in both the cases, a penalty is just implied once the terms and conditions of Google are violated in any aspect. Some common causes for Google penalty can be factors like links from already banned sites, automated queries, keyword spamming, cloaking, duplicate content, hidden texts, link buying and the like. Although these types of factors can any webmaster or SEO consultant, it may happen that a particular action is undertaken by accident or perhaps error, and penalty is evoked.
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