Link popularity is a measure of the quantity and quality of other web sites that link to a specific site on the World Wide Web. It is an example of the move by search engines towards off-the-page-criteria to determine quality content. In theory, off-the-page-criteria adds the aspect of impartiality to search engine rankings. Link popularity plays an important role in the visibility of a web site among the top of the search results. Indeed, some search engines require at least one or more links coming to a web site, otherwise they will drop it from their index.
Link is one of the most important criteria for increasing ranking in the search results. A link is considered a vote for the site, So, a simple rule to increase the ranking of any website in search engines is to increase the number of back links pointing towards a website. There are many types of link building like reciprocal link building,triangular link building, one way link building and underground link building.
Directory submission, articles submission, press release submission are all done with the main purpose to build links. Recipriocal linking if done properly increases the ranking of websites.
