1. A method for providing subscriber-customized documents to clients of multiple subscribers, each subscriber having a computer system on a distributed computer network, the method comprising the steps of: (a) maintaining a main document set on a central computer system on the distributed computer network, the main document set comprising text-containing documents for use by the multiple subscribers; and (b) for each subscriber of the multiple subscribers, providing a subscriber document set containing converted text-containing documents by automatically modifying the text of selected documents of the main document set so that at least some of each subscriber's converted text-containing documents are different from corresponding documents in the main document set and different from the converted text-containing documents of other subscribers, wherein clients of each subscriber have access to corresponding subscriber's converted text-containing documents, wherein the modifications to the selected documents are not made to the text of the main document set, and wherein the modifying comprises converting each selected document by dynamically replacing embedded tags of each selected document of the main document set with subscriber identification data.