A blog is a form of online-diary in which the blog-user regularly publishes articles about different topics and thoughts. The articles are sorted chronologically after the date of the creation and can be commented by the readers as often as they want.

Articles in blogs are mostly being told in the I-perspective and often contain personal opinions, which can be discussed controversial with the readers of the blog. For several years companies also have blogs to give the target group an authentic insight into the company policy. Online shops also use blogs for marketing purposes to impart background knowledge about products which are in need of explanation.