1. A text displaying terminal unit comprising means for memorizing a preset keyword; means for receiving an input text; display means for displaying the information on a display picture domain; means for verifying whether or not there exists a keyword in the input text; means for adding to said text preset displaying attributes of said text and/or a background image associated with said keyword, if such keyword exists; means for transmitting the text information, corresponding to said text added by said preset displaying attributes, as a message, over a communication network; means for receiving said message over said communication network; and display control means for displaying said message on said display picture domain.