You then color over your embossed design with ink of your choice - chalk inks, Distress inks, pigment inks work fine. If you use dye-based ink you will just need to work quickly, and you may not get as smooth results.
Ghost-stamping is similar, but gives you a more subtle result. Use a pigment ink to match your background (white) and use a heat gun to be sure it is thoroughly dry. Then color your background as before. See the difference (below)?
Using these two makes a very interesting card. Here is an example:
You can also use this technique to make backgrounds. It is a little tricky, though, to be able to see where you have stamped...you can see in my example below that the designs are not exactly evenly stamped...
Let's see what you can come up with! I'd love to see your experiments!