Abstract: Apparatus for intercepting data communicated between a sender and a receiver, and conditionally altering that data, the apparatus comprising: an interception unit, capable of intercepting said data, setting information for storing predetermined device settings, access functionality, associated with said interception unit operable to access information within said intercepted data, and a search and replace unit, associated with both said interception unit and said access functionality, for conditionally altering the intercepted data in response to said accessed information and said device settings. The device is useful for dynamically updating web pages and the like and said updating may be made conditional on communication control information such as the identity of an intended recipient as well as data content.