The theory goes something like this: The search engine Powers That Be have decided that if other sites are linking to your site, it must be a winner; therefore, it deserves a boost in rankings (when all else is equal). If you think about it, this makes a lot of sense. People link to good sites, not bad ones. There are a lot of web tools that allow you to check information on links.
Link popularity can be defined as the measure of the quantity and quality of sites that link to your website.. It mainly deals with creating more and more links in order to get high traffic to your site as well as in getting better keyword results in most of the search engines in a span of time..