I think all are important and helpful to popular your products, Business, Brand and website and Search Engines are count them to increase the ranking of your website or increase the visibility of your website. It is more effective if you use natural way means use unique content and build dofollow, relevant, quality backlinks for your website. As Google new update Google Panda, content is more important then other thing so you will use unique and quality content in your Articles, Blogs, Forums, web content... etc. If you use duplicate content, you will get unexpected results.