23. A method of filtering phrases on a computer, the method comprising: receiving a message input by a user on a sender's computer, the message including a plurality of words; conducting at least a partial filtering of the message received on the sender's computer to determine whether the message includes: a non-permitted word, a prohibited phrase, or both a non-permitted word and a prohibited phrase, in response to a determination by the partial filtering that the message does not include a non-permitted word or a prohibited phrase, sending the message over a computer network from the sender's computer to a server for an additional filtering of the plurality of words in the message; receiving an indication from the server that the message has been sent only if, after said partial filtering and said additional filtering, that both of the following conditions exist: each of the plurality of words entered by the sender matches one of a plurality of permitted words, and none of a plurality of prohibited phrases are contained in the message, wherein at least one of the plurality of prohibited phrases consists of a plurality of individual words that are each included in the plurality of permitted words; and receiving an indication from the server that the message has not been sent if each of the plurality of words entered by the sender matches one of the plurality of permitted words contained in a word database, and at least one of said plurality of prohibited phrases are contained in the message.
23. A method of filtering phrases on a computer, the method comprising: receiving a message input by a user on a sender's computer, the message including a plurality of words; conducting at least a partial filtering of the message received on the sender's computer to determine whether the message includes: a non-permitted word, a prohibited phrase, or both a non-permitted word and a prohibited phrase, in response to a determination by the partial filtering that the message does not include a non-permitted word or a prohibited phrase, sending the message over a computer network from the sender's computer to a server for an additional filtering of the plurality of words in the message; receiving an indication from the server that the message has been sent only if, after said partial filtering and said additional filtering, that both of the following conditions exist: each of the plurality of words entered by the sender matches one of a plurality of permitted words, and none of a plurality of prohibited phrases are contained in the message, wherein at least one of the plurality of prohibited phrases consists of a plurality of individual words that are each included in the plurality of permitted words; and receiving an indication from the server that the message has not been sent if each of the plurality of words entered by the sender matches one of the plurality of permitted words contained in a word database, and at least one of said plurality of prohibited phrases are contained in the message. 24. The method of claim 23 , further comprising: displaying the message on the sender's computer prior to transmitting the message to a third party computer; and highlighting at least one of: words included in the message that do not match one of the plurality of permitted words, and/or phrases included in the message that match one of the plurality of prohibited phrases.