Google penalty

A Google penalty is the negative impact on a website's search rankings based on updates to Google's search algorithms and/or manual review. The penalty can be an unfortunate by-product of an algorithm update or an intentional penalization for various black-hat SEO techniques.

Google penalizes sites for engaging in practices that are against its webmaster guidelines. These penalties can be the result of a manual review or algorithm updates such as Google Penguin.

Google penalties can result in the drop of rankings for every page of a site, for a specific keyword, or for a specific page. Any drop in rankings brings with it a major drop in traffic for the site.Google Penguin 4.0 Update

To find out if a website has been affected by a Google penalty, website owners can use Google Webmaster Tools as well as analyze the timing of their traffic drop with the timing of known Google updates.

Google has been updating its algorithm for as long as it has been fighting the manipulation of organic search results. However, up until May 10, 2012, when Google launched the Google Penguin update, many people wrongly believed that low-quality backlinks would not negatively affect ranks. While this viewpoint was common, it was not correct, as Google had been applying such link-based penalties for many years, but not made public how the company approached and dealt with what they called "link spam". Since this time there has been a much wider acknowledgement about the dangers of bad SEO and a forensic analysis of backlinks to ensure there are no harmful links.

Penalties are generally caused by manipulative backlinks that are intended to favor particular companies in the search results; by adding such links companies break Google's terms and conditions. When Google discovers such links, it imposes penalties to discourage other companies from following this practice and to remove any gains that may have been enjoyed from such links. Google also penalizes those who took part in the manipulation and helped other companies by linking to them. These types of companies are often low-quality directories which simply listed a link to a company website with manipulative anchor text for a fee. Google argues that such pages offer no value to the Internet and are often deindexed as a result. Such links are often referred to as paid links.

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Wikipedia