A HOWTO Article, often called just a HOWTO, is an article that usually explains 'how to' use a certain piece of software but can be applied to almost anything including the preparation of fruit salads. While HOWTOs are in many ways tutorials for a specific task, they are not just tutorials as they tend to be much more in-depth, explaining some level of theory along the way, and in that a reader of a well-written HOWTO is more likely to glean some sort of general knowledge about the software in question. Furthermore, a HOWTO often assumes a higher level of basic knowledge on the topic in question.
Red Hat published a book entitled Doctor Linux that consisted entirely of HOWTOs available under free licenses, most of which was available under the GFDL. The book was popular enough that Red Hat made a profit from the sale of the book.