16. A non-transitory computer readable storage medium as defined in claim 15 , wherein the output data defines a graphical is environment in which the visualization structures move.
15. A non-transitory computer readable storage medium containing a program for execution by a computer having a display, the program implementing a message notification system to notify a user about incoming messages stored in an inbox, the notification system comprising: a) an input interface to receive size information and originator information about a plurality of messages in the inbox; b) a processing entity coupled to the input interface for generating message visualization structure associated with each of the plurality of messages, for each message: the processing entity determining a first non-textual visual feature of the message visualization structure on the basis of the size information of the respective message and determining a second non-textual visual feature of the message visualization structure on the basis of the originator information of the respective message; c) an output interface for releasing output data to cause the display of the computer to render the visualization structures, the output data defining a graphical environment in which the message visualization structures are rendered on the display simultaneously and convey information about the messages, their respective sizes, and their respective originator information in a non-textual-list manner, wherein at least one of the first non-textual visual feature and the second non-textual visual feature includes an animation of the message visualization structure associated with the corresponding message.