Wandora is a general purpose knowledge extraction, management, and publishing application based on Topic Maps and Java. More precisely Wandora is an open source desktop application to build and manage topic maps. Wandora has graphical user interface, layered presentation of knowledge, several data storage options, rich data extraction, import and export capabilities, and open plug-in architecture. Wandora's license is GNU GPL. Wandora suits well for knowledge mashups. Wandora is capable to extract and convert various open data feeds to Topic Maps format (see image below). Beyond Topic Maps conversion this feature allows Wandora user to aggregate multidimensional knowledge bases where information from Flickr meets Geonames and Delicious, for example. Read more at documentation.