8. A method comprising the steps of: storing positional information on at least a first avatar and a second avatar; receiving (i) at least one utterance from said first avatar and (ii) at least one utterance strength representing an importance or attention level of said at least one utterance; calculating at least one interest level between said first avatar and said second avatar based on said positional information; generating at least one message from said at least one utterance in accordance with a value calculated from said at least one interest level and said at least one utterance strength; and transmitting said at least one message to said second avatar; wherein, in said step of generating said at least one message, said message is generated from said at least one utterance only when a value calculated from said at least one interest level and said at least one utterance strength is not less than a predetermined threshold value; and wherein said step of calculating said at least one interest level comprises: calculating cosine of an angle between a facing direction of said first avatar and a line connecting said first and second avatars; dividing said cosine by a distance between said first and second avatars; and multiplying said cosine by a normalization factor which satisfies a requirement such that a sum of all interest levels between said first avatar and a number of avatars in a circle having a predetermined radius and centered about said first avatar is unity.
11. The method according to claim 8 , wherein, in the step of generating said at least one message, text data of said at least one message is generated from said at least one utterance such that said text data is displayed in a form varying in accordance with a value calculated from said at least one interest level and said at least one utterance strength.