It's the six-word biography. It's distilling your essence into six little words that tell the world where you're at.
In writing it, you also figure out yourself, a strong statement of what you are, what you do, what you are. It's rather like haiku, paring things down to essentials.
It's not set in stone. Change it every day, if you want, but give it a try.
Mine's "Like the phoenix, I will rise."