Comment 6 for bug 728841

It would probably be possible to be a bit more intelligent about checking the mime-types but I don't think the receptive MIME types are currently exposed; the toolkit is expected to test the widget where it is being dropped.

Dragging a tab to a Terminal does work (it pastes the URL). The extension of that is that I would expect dragging to the Launcher to create a shortcut link to that URL (would probably want to grab the corresponding Favicon and title too).