Backlinks, also known as incoming links, inbound links, inlinks, and inward links, are incoming links to a website or web page. In basic link terminology, a backlink is any link received by a web node (web page, directory, website, or top level domain) from another web node.
Inbound links were originally important (before the emergence of search engines) as a primary means of web navigation; today, their significance lies in search engine optimization (SEO). The number of backlinks is one indication of the popularity or importance of that website or page (for example, this is one of the factors considered by Google to determine the PageRank of a webpage). Outside of SEO, the backlinks of a webpage may be of significant personal, cultural or semantic interest: they indicate who is paying attention to that page.
Link popularity is a term that refers to how many other links point towards a particular website. The term link popularity also has two different forms, Internal and External, which refer to the links coming from the websites own web pages and from other websites. Internal link popularity means the number of links to the website from web pages that belong to the particular website. External link popularity is the number of links from outside sources that lead back to the particular website. In the end, websites with high link popularity have what is called link cardinality or link superiority and have a reputation for being informative, as well as ranking highly on search engines. Link popularity is also an approach that many search engines take when deciding where to rank websites.
Having a high link popularity is an excellent way not only to build a website but to also show others how good the website it. When other web pages link to a particular website it draws additional traffic for that website, as well as giving it what constitutes as votes in the search engine rankings. When two websites with very close levels of search engine optimization and information are being ranked by a search engine, more often the search engine will choose to rank the particular website with the higher link popularity first on search engine results pages.
The philosophy behind link popularity is that the popularity for a particular website will reflect the value of the website. If the website or web page is information rich, well thought out and attractive, common sense says the particular website will have high link popularity.
On the opposite end of the spectrum, websites that are poorly constructed will have less link popularity, and will be less attractive. The importance of link popularity is also measured in several ways. If the particular website or web page that has high link popularity has a high rank on major search engines such as Google, then chances are that the inbound links are from major websites. Inbound links from more obscure websites such as home pages for individuals and blog posts for individuals do not have as much impact on the search engine rank for the particular web page or website. The inbound links from major websites also carry more weight for the link popularity as a concept and not just a number, based on the idea that quality websites produce quality inbound links.