5. The messaging system of claim 1 , wherein the user computer includes a send button for requesting the message sending part to transmit the message, and wherein the user computer disables the send button if at least one of the following conditions exists: at least one of the plurality of words entered by the sender are not contained in the word database, and at least one of the plurality of prohibited phrases are contained in the message.
1. A computer network-based messaging system including a multiple-layer chat filtering system for controlling the content of messages sent by users in the messaging system, the messaging system comprising: a user computer that receives a message, the message including a plurality of words entered by a sender; one or more data storage devices including: a word database including a plurality of permitted words which are allowed to be transmitted, and a phrase database including a plurality of prohibited phrases which are not allowed to be transmitted, at least one of the plurality of prohibited phrases consisting of a plurality of individual words that are each included in the word database, wherein said phrase database is not part of the user computer in the computer network and said user computer is operative to send information addressed to a messaging server system that is remote from the user computer, and said user computer receives an indication from the phrase database of whether said information includes the prohibited phrases; and a message sending part that transmits the message over a computer network only if all of the plurality of words entered by the sender are contained in the word database and none of the plurality of prohibited phrases are contained in the message, wherein the user computer provides a display of the message to the sender prior to the message sending part transmitting the message, and wherein the display highlights words included in the message that must be removed before the message sending part will transmit the message over the computer network.