Link building in regards to search engine optimization is something that is extremely dynamic. If you are not willing to change your approach your efforts will simply vanish. To be honest with you we really hate the phrase “link building”. SEO is all about marketing your website while using components that are important for search visibility. The problem is many companies and individuals over the years that have simply beat certain popular efforts into the ground leaving Google to have to clean up the mess and make them irrelevant.
In this great infographic piece SEOBook put together a great image describing how certain organic links have been devalued over the years. Take a look.