QUOTE: “The score is determined from quantities indicating user actions of seeking out and preferring particular sites and the resources found in particular sites. *****A site quality score for a particular site**** can be determined by computing a ratio of a numerator that represents user interest in the site as reflected in user queries directed to the site and a denominator that represents user interest in the resources found in the site as responses to queries of all kinds The site quality score for a site can be used as a signal to rank resources, or to rank search results that identify resources, that are found in one site relative to resources found in another site.” Navneet Panda, Google Patent

QUOTE: “(Google Panda) measures the quality of a site pretty much by looking at the vast majority of the pages at least. But essentially allows us to take quality of the whole site into account when ranking pages from that particular site and adjust the ranking accordingly for the pages. So essentially, if you want a blunt answer, it will not devalue, it will actually demote. Basically, we figured that site is trying to game our systems, and unfortunately, successfully. So we will adjust the rank. We will push the site back just to make sure that it’s not working anymore.”  Gary Illyes – Search Engine Land
Either porn SC or Ads containing porn on non­Porn pages can be very distracting or even upsetting to users. Please refresh the page a few times to see the range of Ads that appear, and use your knowledge of the locale and cultural sensitivities to make your rating. For example, an ad for a model in a revealing bikini is probably acceptable on a site that sells bathing suits. However, an extremely graphic porn ad may warrant a Low (or even Lowest) rating.”
In addition to on-page SEO factors, there are off-page SEO factors. These factors include links from other websites, social media attention, and other marketing activities outside your own website. These off-page SEO factors can be rather difficult to influence. The most important of these off-page factors is the number and quality of links pointing towards your site. The more quality, relevant sites that link to your website, the higher your position in Google will be.