There is disclosed a method and apparatus for transmitting a message to at least one group of users selected from a population of the users. The method comprises the steps of assigning to each member of the one group a common characteristic or indication, collecting from each member of the population an address to which the message may be sent, selecting the common characteristic of a group of message recipients and determining therefrom the users of a particular group or groups based upon the selected common characteristic, whereby messages may be quickly and efficiently sent to all of the users of the selected group(s).