A tutorial is a method of transferring knowledge from one person to another and can take a number of forms. While a tutorial can sometimes be referred to as a small class of students, from the interest of the internet we are more concerned with what is referred to as online training.
Online training can itself take on many forms such as audio, video, and written form. The written form of tutorial is probably the most common since it requires little else other than a text editor to generate. The online video course is considered by most to be the most versatile since not only can you see what is going on, you can hear the instructor explain the tasks at hand.
Not only are there a number of companies who provide a wide range of online tutorials, there are many programs for creating online learning, such as the video recording software Camtasia, and e-learning programs like Adobe Director and Adobe Captivate. It is hard to tell where the next great idea for tutorials will come from, but no doubt it will involve the internet.