Link popularity is a major factor major search engines use to rank web sites.
This refers to the number of links to your site, from other sites on the internet. The more links to your site (especially from other content rich sites that are considered relevant to yours), the better. It is these links and their relevancy that add weight to your case when the search engines are ranking your site.

Reciprocal links – where you swap links with another site – should not be discounted. They won’t carry as much weight as a one-way link but, every little helps.

Links carry more weight if they are surrounded by relevant text rather than appearing on a ‘links page’ and a text link should appear as the keyword or phrase you’re trying to optimise for rather than ‘click here’.

Link building can be time-consuming, especially building relevant links. Of course, if you have Good SEO content then other, relevant sites will be more inclined to link directly to yours.