A very interesting article. I was particularly interested in the bit about playing in different keys. I think it is a bit boring, especially for the audience, when you only play in one key.
Thanks for the heads-up! Interesting article. By the way, I used my recently-acquired "Play Ukulele By Ear" knowledge on New Year's weekend to accompany a family member who was playing "Auld Lang Syne" on the piano, so thanks for that too!