Earned links have been considered the holy grail for a better ranking in search engines. We want to know what percentage of links is earned links in the link universe. The ratio of backlink count (root domains) to Facebook sharing count is used to measure the degree of link promotion. A page with 100% earned links will have a lower Link/Like Ratio (LLR), and a page with link promotion will have a much higher LLR. By comparing LLR of pages without link promotion with LLR of pages with link promotion, we found that only 5% of links are earned links, and 95% of links are promoted links in the link universe. http://www.4th-media.com/seo/earned_links.php
Google wants webmasters to get only earned links to rank higher. But in reality, a page on a high-traffic site like CNN will only earn less than 10 links in a year.