A system for categorizing transactions includes a collection function gathering information concerning transactions, including at least date, description and amount of the transactions, for a particular person or enterprise, and a processing function categorizing individual ones of the collected transactions according to at least part of the transaction description. In preferred embodiments of the system a variety of categorization methods for collected information may be utilized including at least categorizing by providing individual categories according to category definition entered by a specific user or on behalf of an enterprise. Categorization may also be done for a first plurality of persons or enterprises according to category definition entered by a second plurality of persons or enterprises, or categories are developed from information taken from communication between users and the system. Probability algorithms may also be used in developing categories.