Links and link popularity can really affect your seo efforts positively or negatively. See how it works, the plain english version.
Link building can be a central part of your online marketing effort whether as a method of getting traffic directly from other sites or as a part of your SEO efforts.
Links are the roads and pathways of the web, they connect our pages to other pages on our sites (Internal Links) and they connect our sites to other sites (External Links). In the real world the more roads and pathways to a particular location the more popular (and populated) that location tends to be. If the roads and pathways all have signs on them telling us where they lead...