I think that all depends on what your goals are and especially your marketing budget.
Obviously the paid form of marketing (PPC, PPV, Banner Ads, etc.) will give you the fastest results. But content marketing (articles, press releases, blogs, etc) allows you to create a trust with that person that just opted in to your website.
Remember, a person buys from someone they trust. So in my opinion, it eventually all comes back to using content and socializing to finalize any new sale or populate a new business partner.