Jun,
The content is stored as it is typed, and processed on display. It would be possible to turn this into a form builder widget, but that isn't done yet.
It probably should work like the enhanced text widget, and create a mime type of text/wiki or something similar.
But, the magic part is that if you request a non-existant URL or type a link in square brackets, you can create a new page (if you have write privilege.)
