Adaptive hypermedia on the Web : methods, techniques and applications

World Wide Web lets information providers (potentially) reach millions of people located all over the world. These users form a very diverse crowd. No single presentation of the information an organization wishes to distribute will be suitable for all types of users that organization wishes to address. Adaptive hypermedia techniques make it possible to provide each individual user with the information and presentation he or she needs, based on an internal representation of that user, called the user model. The user's goals, preferences and needs may change over time. An adaptive Web-site observes these changes, updates the user model on the fly and uses it to adapt the presentation to the changing circumstances. This paper gives a very brief overview of some existing adaptive hypermedia methods and techniques. Both the (textual or multimedia) content of pages and the links between them can be adapted. The paper indicates which Web technologies are (sometimes or typically) used to realize adaptive Web sites. This includes both technical hacks to make it work and authoring tools intended for subject-matter experts who are not (necessarily) very computer or hypermedia savvy. Through examples of applications we show reasons for making a Web site adaptive in certain ways. Adaptivity must be used with caution in order to avoid Escher effects that might turn browsing through an adaptive Web site into an adventure game instead of making it easier and more effective. keywords: adaptive hypermedia, adaptive Web sites, user modeling, adaptive presentation, adaptive navigation, adaptive authoring tools