Content marketing and link building both have their merits in the realm of search marketing.
However, the tale of the tape reveals that content marketing has a distinct advantage over link building for marketers.
Alternatively, if you create a piece of content for a site, you will know how many links that content has generated, how many social votes it has, how many referral visits it's got, how much organic search traffic it's created and which search terms achieved rankings etc.
Compare this with competitor analysis or submission based link building there's a common trend there which shows that these websites are not linking to you because they like you, they're linking to you because you asked them to (or even paid them to).
To move forward, it's vital you hire the right people and building a content team is much less of a risk than building an SEO team is ever likely to be.
So instead of focusing on whatever type of link hasn't been hit by a penalty yet make content marketing the center of your SEO strategy instead.
Social media is all about people if you want to assess a company's social strategy, it's not just about a brand or fan page it's about the people who work there, too.
And who wants to write creative content and be social online, building up connections to help you share that content?