The web and its associated technologies Ð Cgi-scripts, JavaScript and Java Ð have become a platform for the development and deployment of applications. Such has been the impact of these technologies that their combination has been likened to an Expert System Shell, and referred to by the term WWW shell'. This WWW shell it is claimed is particularly adapted to the development of collaborative applications. This paper challenges this claim on three grounds: browser incompatibilities limit the potential bene®ts from client-side processing technologies; the generic Common Gateway Interface as an application delivery mechanism is inadequate and the networking restrictions on Java applets constrain effective use of the latter as dedicated interfaces to remote applications. This argument is illustrated with respect to three case studies of practical collaborative applications of WWW shell technology. The paper concludes by exploring the implications of new server side technologies, in particular Java servlets for the future development of the WWW shell and the evolution of an Active Web'.