Making Customisation Intelligible

Appropriation often involves adaptation and customisation. The problem with standard approaches to
customisation is that, by specialising the behaviour of a system to one individual or group, they
simultaneously make the system less useful or intelligible to others. So, while customisation can support
appropriation through the adaptation of technologies to immediate local needs, it also interferes with the
ability to share information with others. (This is a familiar problem to programmers, who must balance the
issues of change and reuse; we need solutions that tackle these problems in other domains without
introducing the rigid structures of software.)
One setting in which we have recently encountered this is the management of a large collection of
workgroup documents in a local government organisation (Trigg et al., 1999). We have been developing a
prototype system called Macadam (Dourish et al., 1999) which attempts to address these issues. Macadam
is a system for managing documents according to customisable category structures. However, when a user
or a group customise the category structure, Macadam retains the relationship between the original and new
structures. In this way, when document collections are presented to a different user who does not share the
same set of categorisations, the customisations can be “unrolled” and so the documents can be presented in
a way that makes sense to whoever is looking at them.