I believe it's a great practice for anyone to sit down for a few minutes each day to reflect upon what has been learned. Writing daily is a practice I learned from Seth Godin and, having tried it for over a week now, I am certain that it's a practice I will continue.
Not only has it made me more articulate, but it has also forced me to slow down. I find myself more aware of my surroundings and analytical of ideas. As a computer engineer by profession, my daily routine has consisted more of writing code rather than English. So, figuring out how to express my thoughts through words has been a fun challenge for me.
I am writing for me and for nobody else. While I am no where near a perfect writer (if such a thing exists), I can tell that I am improving. And I'm happy with that.
I can't wait to continue this practice over the upcoming years and discover what I learn.