19. The memory of claim 14 wherein the history apparatus further comprises: a parser, operatively coupled to the user interface, for parsing from the user data description a description component which comprises one or more instances of one or more component elements of the collection of two or more elements; wherein the selected category is associated with one of the component elements.
14. A computer readable memory which includes a history apparatus, the history apparatus comprising: a user interface which converts signals generated by a user to user data which is stored in the memory and which has a user data description, the user data description comprising one or more instances of one or more selected elements of a collection of two or more elements; a history database, operatively coupled to the user interface, the history database comprising two or more categories, each of which is associated with a respective one of two or more elements of the collection; and a user data classifier, operatively coupled between the user interface and the history database, for storing the user data in the history database in a selected one of the categories which is associated with one of the selected elements; and a user data retriever, operatively coupled to the history database, for retrieving user data from the history database, the user data retriever comprising: a category selector, which is operatively coupled to the user interface and which specifies, in response to signals generated by a category selection gesture of the user, a selected one of the two or more categories; and a user data selector, which is operatively coupled to the user interface and which specifies, in response to signals generated by a user data selection gesture of the user, selected user data of the select category.