Google's indexing algorithms assign internal ranks to individual pages of a website so that a given page receives a fair opportunity to appear in a high position in SERPs when a user inputs a search query for a term relevantly featured on that page. Up until 2010, Google's indexing algorithms gave equal amounts of attention to every individual link on a page; this resulted in every page on a website being analyzed equally thoroughly. However, Google patented a model in 2010 that has since allowed its algorithms to consider some links to be much less valuable than others by predicting the likelihood that an average Internet user will refrain from clicking it. At the most basic level, Google's patent means that its algorithms will not give much weight to any link that lies near the bottom of a page. This model was put in place because users are quite unlikely to look at the very bottom of a page and follow a nondescript link that happens to be there. It does not matter whether this link is placed at the bottom of a single page or if it is part of a content footer that is used across every page on the website. In general, visitors direct the majority of their available attention toward the content that a given web page displays at its highest portion when it is first loaded. Modernized web design takes Google's "reasonable surfer" model into account in order to make sure that the most relevant portions of a website's content are the first things a given visitor sees. Links to the most appropriate pages of content are often featured conspicuously in navigation systems placed near the top of every page on a site. Websites that include content footers typically do so in order to include links to legal and technical information pages that are more important to those sites' capacity to do business than to the actual products and services they present to visitors. Such pages list terms of service and privacy policies that visitors generally are not interested in reading. For more information click here https://www.reddit.com/r/SEO/comments/93fj7k/sitewidefootervssinglepagelinksforseo/.