Abstract: A system and a method automatically inform Internet users in a 3-D virtual reality environment of other users having similar interests by using the information of the users. The system for determining a second user who has similar interests with a first user's information in a virtual space includes a calculation part for calculating a similarity between the first user and the second user, and a determining part. The calculation part monitors whether there is the second user in a predetermined distance from the first user in the virtual space, and calculates an information similarity between the first and second users by using the users' information stored in a storage part of the is virtual space. The determining part determines whether the first user is similar to the second user or not.