1. A presence-based seamless messaging method, comprising: from within a computing environment executing on a processor and configured for sending a message via a user interface associated with a first communications medium, detecting a current live presence of a potential message recipient who can be reached via a second communications medium; running contemporaneously multiple communications programs for accessing the first and second communications media to allow instantly sending a message via one of the communications programs; transforming the user interface to include an option of using the second communications medium; activating the second communications medium in response to the detecting; displaying a one-click control option for transitioning message delivery and message composition to the second communications medium when the potential recipient is present to the second communications medium; removing display of the one-click control option when the potential recipient becomes non-present to the second communication medium; transferring automatically upon actuation of the one-click control option at least part of an unsent message from a message composition environment associated with the first communications medium to a message composition environment associated with the second communications medium when the first communications medium becomes unavailable; and transferring automatically upon actuation of the one-click control option at least part of an unsent message from a message composition environment associated with the second communications medium to a message composition environment associated with the first communications medium when the second communications medium becomes unavailable.