Here's a tutorial showing how to create a smoke text with Autodesk Smoke, using a few simple nodes to animate the text: Glow, Blur, 2 different Deform nodes, GMask and Blend & Comp.
This video shows the step by step setup, node after node, and shows screenshots of each keyframe's field values. Just pause and pinpoint the field highlighted in yellow, which is or are the fields corresponding to the keyframe.
The detailed steps are listed here http://www.vizpictures.com/vfx/smoketext/
How to use expressions in action to make a cool counter contraption. Shows how one prototype expression can be added to multiple channels using the SelectionOrder keyword, how to isolate columns of numbers, and otherwise fill your head with expression ideas.
Prototype Expression: if(((trunc((control.position.x/1))%10)==1),0,100)
It may be easier to paste that rather than type, but it should be clear what to do in the demo.