Link Popularity and Inbound Links Explained
Link Popularity is simply a measure of the number of links that point to pages within your website. Each link that points to a page within your website from another website is known as an Inbound Link (IBL) or a backlink. Converserly, Outbound Links (OBLs). are links from your website to other websites.
Increasing your websites Link Popularity by increasing the number of IBL's your site has is an important part of promoting your website. Not only do the IBL's lead visitors to your site, but they also lead Search Engine Spiders to your site and increase your Page Rank thereby increasing your placement within Search Engine Results Pages
You can find out how many IBL's a web page has by typing link:yourdomainname into a search engine.