Disclosed is an electronic bulletin board system, which communicates with a user computer via a network, and mediates information exchange therebetween by an electronic bulletin board function. The electronic bulletin board is accompanied with a database of a notable words collection storing a plurality of words that are appropriately selected, each word in which is linked with a corresponding URL. A message text from a user computer is checked by using the notable words collection. When the message text does not include a notable word in the notable words collection, the message is posted on the bulletin board. When a notable word is found in the text, the notable word in the message text is converted into a hypertext format having the URL to which the word is linked as a link destination, and the message is posted on the bulletin board.