Aaron Gotzon on The Ontological Geek:
It is the responsibility of videogames to teach us how to play them. Before the game can even really strut its stuff, it has to play the role of teacher, and show us what plastic-thingies do which murdery-kill-ma-bobs.
More than that, the tutorial has to be woven into the game in such a way that it doesn’t manage to detract from the game itself, or distract from that immersive element which is key to most experiences of fiction. In the ‘biz we call it “suspension of disbelief.”
What about your web application? How does it teach users to use it? As with games, there are universal concepts, such as typing, clicking, and related actions that all computer users know to do.
But when it gets down to learning how to use the actual application, how could you teach that person to use the application in a gradual and natural way? For example, what if WordPress had a user only be able to create a title and a post body the first time? Then the second time, the user is told how to add a tag or use a category—and you added little bits each time they used it?
Of course, power users don’t need this, but people who are new to an app and might not have a bunch of computer experience outside of using email or Office might be completely overwhelmed the first time they use your app.