To tackle the demand for support to building CSCW applications, one approach has been the provision of reusable components and infrastructures. Regarding the need by CSCW applications to use context information to adapt their services according to users? and groups? needs, the literature has reported on the provision of models and associated implementations allowing applications to represent, share and report relevant context information. In this paper, we propose that CSCW applications take advantage of the benefits provided by Web Services, allowing the interchange of context information between applications and infrastructures in heterogeneous environments. We present the Context Kernel Web Service and how typical operations demanded by CSCW applications can use it to store, retrieve and exchange context information via the Web.