Next-generation Grid applications will operate within and across many heterogeneous network types, will employ a wide range of device types ranging from supercomputers to sensor motes; and will require many more “interaction paradigms” than merely RPC and message-passing. The Open Overlays project proposes a middleware approach to satisfy these emerging needs. In this paper we describe an application scenario, wildfire management, that encompasses these needs, and our approach to constructing a component of this scenario, a collaborative workspace tool (svgCWE). This is being constructed using Web technologies: SVG and RDF. Information in the collaborative workspace is regarded as an annotation of the workspace resource which can be described with an RDF model. The architecture of svgCWE is designed so that a variety of different kinds of RDF repository (centralized, replicated and distributed) can be used. The paper describes the first prototype of svgCWE and draws some tentative conclusions about the advantages of the approach.