A packet switching system includes a plurality of switch fabrics connected in cascade and a plurality of buffers respectively connected to the plurality of switch fabrics. The system includes a portal computing device having a customized collaborative web portal server application, and a user computer operatively coupled to the portal computing device, where the user computer includes a user interface of a web browser and is adapted to display a hierarchy of interlinked portal web pages provided by the portal computing device. The controller selects an image bubble based on the three-dimensional location. In image deletion, the background image side is shaded off.