LiveDoc offers a slightly different take on the problem addressed by Data Detectors. The same parsing engine and scripting system is used as before, but the application displaying the document has been modified so that holding down the control key causes the application to run the parser on the text in the window, and add visual highlights to the bits of text that it knows how to handle. Pressing the mouse button down on one of these highlights reveals the same kinds of action menus and submenus as were shown by Data Detectors.
The advantage of this approach, of course, is that the manual text selection task is avoided; LiveDoc itself is able to find the bits of actionable text and offer actions on them. However, these capabilities require modifications to applications, or, better still, to the APIs that underlie all the platform's applications. The recent announcement of SmartTags by Microsoft is an illustration of how these kinds of capabilities can be implemented as operating system-level services.
You can find out more about LiveDoc here.