SpaceTag: an overlaid virtual system and its applications

SpaceTag is an object system on which each object called SpaceTag can be accessed only from limited locations and a limited time period. Its applications include entertainment systems, advertisement services, bulletin board systems, and personal communication systems. For one-way communication, they are broadcasted from the server; for two-way communication, users can cut and paste SpaceTags between their portable PCs and the real space. The SpaceTag system is a location-aware information system, as well as an augmented reality system because it attaches information to the real space. However, we categorize it as an overlaid virtual system, because it has no direct link to real objects. It can be realized as a public service without causing drastic change of this society, and without much cost.