This contribution is based on Habermas' theory of communicative action and his distinction between lifeworld and social subsystems like the economy, science and public administration. This distinction does not only help in understanding the role of generalized action orientations and symbolic mechanisms in social subsystems, one important conclusion is that evolution and transition of orientations and mechanisms require communication and discourse: communication about problems, about problematic orientations, new ways and mutual insights etc. IT support in this regard (conversation support) plays a completely different role than "normal" information systems that are aimed at the stabilization of established orientations (like in economy profit maximization in combination with Taylor's efficiency thinking). This allows discussion of different IT solutions with respect to their capabilities supporting the transition phase of sustainable development, as well as their contributions to modified or new generalized action orientations: environmental management information systems (EMIS), specialized modeling tools (e.g. life cycle assessment tools) but also all-purpose tools such as Excel, Email and web-based social networks.