Thesauri are considered as an optimum between maximum ontological modelling (best knowledge mapping) and minimal alphabetic ordering (less expensive access). From this point of view a swift history of its evolution is provided. The recent evolutions in Internet searching are also analysed from this perspective. In this context, there is an immediate role for thesauri to ensure interoperability and feed up the new Internet semantic engines; and in the long term as a simple semantic user interface for resource discovery and navigation, which ensures proper transparency and control by the user who wants to take the effort to supervise and analyse its search processes. It is proposed that better devices for ensuring semantic sorting are provide...