1. General situation and objectives

This introductory section recalls the context in which application modeling for the Web is approached. On the one hand, the Web is not simply a collection of a few billion static "pages" written by their authors: it is also, and above all for companies, a means of developing computer applications that interact directly with the end user. On the other hand, unlike the users of many other IT applications used in the workplace, the standard Web user is not a specialist operating daily with the same application as part of his or her job, but just an occasional, free user. They often discover the application they're interacting with the moment they use it. They can easily change it if they're not satisfied. Application design needs to take this into account. Finally, it's important to note that navigation is the common feature that underpins interaction in all Web applications. It is by no means...