Mountain Lion here. I can select text using the Three finger swipe. But to drag that text (for copying into another window, for example), I have to resort to the old fashioned (:)) press-click-on-trackpad-and-drag-with-second-finger. Is there is some way I could drag the selected text via the same three finger movement (maybe by pressing some modifier key to signal that I wish to drag and not select)?
After selecting the text, place your three fingers on the trackpad and don't drag for a half-second or so. Then, slowly drag your fingers until you see the I-beam cursor turn into the mouse pointer. Then you can three-finger drag normally.
When using click and drag for text, you need to hold the click for a half-second or so before the system realizes you want to drag the text instead of selecting it. This procedure replicates that with the three-finger drag gesture. (As you get better at this place-hold-slow-fast gesture, you can speed it up to a point where you're comfortable with the speed and it still works.)