http://www.nbcnews.com/business/starbucks-jam-over-duffingate-8C11361420

The real irony here is that “duffin” is a weak trademark based on descriptiveness, and somebody other than the parties listed in the above article has already received a U.S. registration (on the Supplemental Register) for “DUFFIN.” (Even more ironic is that the DUFFIN registration is on the Supplemental Register not because the Examining Attorney picked up on the “doughnut + muffin = duffin” descriptiveness, but because “Duffin” is apparently a rare surname, thus it went on the Supplemental Register.)