A blog post is a piece of writing that references a certain topic.
In Digital marketing, a blog post is a method of generating organic traffic for a marketer by optimising SEO within the blog itself. By using credible sources, and clear and concise information that relates to the product or service being offered by the marketer.
An example can be a website that sells gaming chairs, they create a blog post about how having a gaming chair can increase your focus & alleviate strain on your body. Within the blog post, references to credible information and to the marketer (in this case the gaming chair website) are made via hyperlinks etc.