Google’s Penguin update was aimed at decreasing search engine rankings of websites that violate Google’s guidelines by using black-hat SEO techniques such as keyword stuffing, cloaking, participating in link schemes, and the deliberate creation of duplicate content. The update has also affected sites not engaged (knowingly) in black-hat SEO. From Search Engine Journal and Link-Assistant.com, here's an infographic on how to do a Penguin-savvy inventory of your site, including: