Is the cupcake craze over? Earlier this month, Crumbs Bakery closed its doors. But Likeable Media wasn't ready to let go. We decided to sell what was supposedly “the last cupcake from Crumbs Bake Shop” on eBay. This piece of real-time marketing went wild, garnering coverage on USA Today, CNBC, TIME, Jezebel and many more. In this week's episode of Carrie's Corner, Carrie Kerpen identifies three things you can learn from this innovative campaign.