Smoke control like fluid control

Alright, so I was wondering whether one could simulate some smoke that morphs to a particular shape, like a word, or a character or something like that, before going back to smoke again. It’s been seen in some commercials and stuff I think, and it just seems like a very sleek effect, except I have no idea how to make it happen in Blender.

I know there is a similar thing with fluids, in the way that you can set an object as Control object.

Anyone know a way to achieve this? Perhaps the old school way with particles?