Google Maps is increasingly being used as a tool for publishing geographic data on the web. As part of the NCeSS GeoVUE project we have developed the GMapCreator software to allow us to automatically build web sites from thematic data contained in shapefiles. By pre-rendering all the data as tiles using the same method used by Google Maps to store the map and satellite views, it means that anyone with access to space on a web server can upload and publish thematic maps. It also means that large datasets, for example the whole of the UK at postcode unit level, can be visualised. This is in contrast to using the Google Maps API where the browser can only handle small numbers of point or line vertices. This also eliminates the requirement for complex hardware to build maps on the fly, as in other web-based mapping system architectures, but imposes limits on what GIS functions are possible in such a system. Ultimately, the aim of the GeoVUE project is to make geographical data more accessible to the general public, so we can move beyond a simple tool for publishing maps and start looking at how data from different sources can be compared and visualised. This is the concept behind the MapTube website that is being launched by CASA, where maps created using the GMapCreator tool can be shared with other users. MapTube works by storing links to other Google Maps already on the web that were created using the GMapCreator software. The benefit of uploading a link to a map is that it then becomes very easy to visually compare information from multiple maps, so, for example you can see the London subway map over a plot of population density. In this talk we launch the MapTube website and demonstrate some of its features.