There are two clearly-identified Google penalties which are Google algorithm update and Google manual action penalty.

I - Google Algorithm Updates

Google algorithm updates are frequent actions intended to improve the performance of Google search results.

We cannot rightly tell how frequent a Google algorithm update is because Google doesn't disclose this to the public. However, when there is a widespread shift in search ranking of websites, then we suspect there has been a recent update.

Most often than not, an algorithm update may leave most sites intact or result in slight movements in search ranking.

II. Manual Action Penalty

II - Manual action penalty is a punitive action taken by Google personnel over a website that is found to have broken Google Webmasters rules.

Some of these violations include: buying lots of inbound links, having lots of spammy backlinks, or using duplicate content on your site.

The results of a Google manual action penalty are way more severe than that of a Google algorithm update. And that's why this guide was created to help you discover and resolve any Google manual action penalties you find yourself in.