Geosocial networking services allow users to create, use, and share information and to communicate with other people regarding geographical locations and time. Geosocial networking services generate large amounts of spatiotemporal contents that mainly include information about personal interests, activities, or real-life experiences. This paper discusses a new geovisualization tool named StickViz that helps retrieve k-neighbors by considering the spatial, temporal, and thematic interests of users over geosocial networking services. In particular, we define phenomena of interest for combining user interests with respect to location, time, and topic and propose a phenomenon-based k-neighbor query to find people having similar interests in spatial, temporal, and thematical dimensions. Moreover, we use a three-dimensional (two spatial dimensions and one temporal dimension) space so that the queries and spatiotemporal contents can be represented in the same space. Finally, we present a prototype of StickViz to navigate spatiotemporal contents and search k-neighbors on the basis of the predefined phenomena of interest through three-dimensional visual interfaces.