1. A message distribution apparatus for distribution of a message submitted by a user by means of a terminal connected to a communication network to a previously unknown group of receiving users; said message distribution apparatus comprising: (a) an access to a database which stores a semantic network data model comprising terms linked to each other by at least one of semantic relations and a social network data model comprising users linked to each other by social relations; (b) a mapping engine which is adapted to map at least one term being associated with the submitted message to at least one of terms being associated with users of said social network data model and terms of said semantic data model for generating at least one group of potential receiving users for said submitted message; and (c) a distribution engine which is adapted to distribute the submitted message of said submitting user via said communication network to a group of receiving users filtered from the at least one generated group of potential receiving users.