Content marketing: involves creating and freely sharing specific, expert content to help the community understand one or many subjects dealt with on a specific website.
Content marketing (also known as "content recommendation") is any marketing format that involves the creation and sharing of media and publishing content in order to acquire customers. This information can be presented in a variety of formats, including news, video, white papers, e-books, infographics, case studies, how-to guides, question and answer articles, photos, etc.
Content marketing is focused not on selling, but on simply communicating with customers and prospects. It is a mean to pull interested people or prospects into the website trying to convert them into customers or free subscribers, and customers into repeat buyers.
On the web, content marketing is "simply using content — news, feature, or otherwise — to commercial advantage. Examples of web services that provide content marketing are Outbrain, BlogUpp, and Taboola.
Source - wiki