This chapter illustrates the range of applications involving 3D data that have been annotated with some sort of meaning. It considers applications where the 3D data are analyzed to extract usable shapes or properties from the 3D data. The chapter provides examples of semantic applications where the 3D data contribute to the recognition of the general nature of the observed scene, the recognition of the type of object that is being observed, and the specific instance of the object. Behavior analysis typically starts from video data, and with the availability of 3D video sensors, additional time-varying information can be extracted from the 3D data to improve accuracy or provide statistics for e.g. health or performance monitoring. The chapter reviews applications where the information extracted from the 3D data is related to position. Examples include estimating an observer's position, such as on a mobile robot, an external object's position, or the configuration of the tracked object.