The first concept that I sent this client was a bit more elaborate. Each version then simplified into this current form. We also provided another version of this animation against a black background. Simplicity often develops into elegance which I think works great with this logo design and animation.
Animating mask keyframes overtime allows one to duplicate this "writing on" effect. Sometimes it is helpful to break the letters apart to make it easier to animate.
Logo Animations: spinmylogo.com
Explainer Videos: pandamotion.com