Link popularity refers to the total number of links that a search engine has found for your web page. The more web sites link to your web page, the higher the link popularity of your page. A high link popularity contributes to a high search engine ranking.

Note that link popularity is measured only for single web pages, not for the whole web site. Your web site can have several web pages with different PageRank numbers.

The idea behind the link popularity concept is simple. The more other web sites link to your web site, the more important your site must be. Other sites wouldn't link to your site if there wasn't something interesting on your site or if your web site didn't contain any special content.

That's why link popularity is now one of the most important factors for search engines when they rank a web page.

However, you cannot get a high link popularity by submitting your web site to thousands of FFA (free for all) link pages. Not all links are considered equal by the search engines. It does matter who links to you and how they link to you.