14. A system for recognising a numeric or alphanumeric sequence of characters in a document, said sequence conforming to predetermined rules and representing user identifiers for identifying users in a communications system, the system comprising: a component for identifying a country of origin of the document, the determined country of origin capable of being changed by a user; a store holding rules relating to a format of said sequence associated with the different countries; a search component arranged to search the document to identify any sequence in the document satisfying a format for the determined country of origin; a component to determine a rate associated with said sequence; a converter arranged to convert said sequence into a call format for the country of origin of the document identified by the component for identifying; and a tool for instantiating an object for returning any such sequence and the determined rate in a currency associated with the determined country of origin.
15. A system according to claim 14 , which further comprises a web browser arranged to locate a page on a world wide network, said page constituting said document.