Design issues in adaptive web-site development

For almost a decade people have been developing hypertext or hypermedia applications that adapt to some "features" of their users, like knowledge or preferences [Brusilovsky, 1996]. Recently some adaptive application environments have become available that use World Wide Web technology. Examples of such systems are Interbook [Brusilovsky et aI., 1998] and AHA [De Bra & Calvi, 1998]. The adaptation can range from a simple (automatic) selection between different versions of some information pages to the completely dynamic generation of all pages from atomic information units and the automatic generation of all hypertext links. This paper sketches a general architecture for adaptive Web-sites by building on existing models such as Dexter [Halasz & Schwartz, 1994] and IMMPS [Bordegoni et aI., 1997]. More importantly, this paper identifies issues in adaptive Web-site design for which no general approach or solution appears to exist (yet). These include (but are not limited to): the separation of a conceptual representation of an application domain from the content of the actual Web-site, the separation of content from adaptation issues, the structure and granularity of user models, the role of a user and application context, and the communication between different adaptive Web-site "engines"