This is an interesting article on SEOMOZ posted by Randfish. He describes that SEO link building is dead and hence those trying to acquire links as a means to build ranking will no longer be counted and even be penalised. So what does this mean as far as building links are concerned. It means that, try not to build links but try to earn your links. What this means is that, earning links that will bring you relevant traffic. This means, no more anchor texts, no more directory submissions, link exchanges reciprocal links, buying links but instead you need good links that you have earned.
So what constitutes of earning links? They mean social sharing. For instance if a visitor is on your site and likes your content, they will share and if its that good then it will get more shares and eventually magnified. So you have earned links.
Earn links directly by content, this means that the content is so good that people want to link to you, embed your story, write about it, blog about it and refer you to others. Again you have earned links. A link from a powerful site from your own industry is worth hundreds of article directory submissions.
Watch this video to understand to understand more about link earning means.