http://www.suasnews.com/2016/01/4111...dy-registered/
From Huerta's speech at CES 2016 yesterday.
"Registration is simple – and it’s mandatory for aircraft that weigh between 0.55 pounds and 55 pounds. You enter basic information – name, address and email address – into our online system, and read and acknowledge our basic safety guidelines. "
Pretty cut and dry in my book.
Mike