From the campaign:
Worldspinner makes it easy to create your own richly detailed fantasy world in minutes, including continents, mountain ranges, cultures, kingdoms, cities, and more. Then, delve as deeply as you like into customizing your world. You can create beautiful maps without spending hours with paint tools, and without needing to be an artist.
Worldspinner is a tool, not a game. It doesn’t replace your creativity, but multiplies it. It is hosted online, so you don’t need to download anything and it is available anywhere. The technology is almost complete; the maps and screenshots you see below are all real examples from the working system.