Link Popularity
Link popularity is an assessment of the number and quality of hyperlinks coming to a particular webpage. Link popularity is a determining factor in how high your webpage ranks in search engine result pages (SERP) of most search engines, such as Google's PageRank. There are many SEO techniques that increase web traffic to your webpage by increasing your link popularity.
In the 1990s, link popularity was based solely on the number of hyperlinks coming into a webpage. However, this was quickly exploited with link farms, spamdexing, Google bombing, and other techniques that manipulate a search engine through use of links. These spamming techniques could force obscure, content-poor web pages up to the top of search engine results pages. Some search engines like Yahoo and Google changed their algorithm so that link popularity was determined on the quality of the links, and not just the quantity. Links from relevant websites "count" more toward increasing your ranking in search engine results. Links from reputable, large, and high-ranking websites also "count" more. Links from banned or questionable websites can hurt your ranking. The idea behind this is to improve the quality of search results so that search engines put high-quality, informative, useful content higher up on search engine results pages (SERPs).
Technically, link popularity includes both links coming from pages within the same website (internal links) as well as links from other websites (external links). Often, however, the term link popularity may refer solely to external links. Online, you can find a number of link popularity calculators and tools designed to help webmasters and website owners determine their link popularity.