The number of quality relevant links is one of the metrics Google uses as a ranking factor. There are so many legitimate ways of link building that works well, but you have to earn them now, instead of just buying them..
As Paddy Moogan said via Internet Sales Drive
You should be “focusing on building links that you won't have to take down in 2014. :)”
Today, I want to contribute some of my link building methods and how to earn editorial links through email outreach.