For many brick-and-mortar retailers, this year has been what one analyst called "a bloodbath." Major stores, including Target, Macy's and Kohl's, all reported poor first quarter sales. But dollar stores are thriving. Dollar Tree, with about 14,000 locations in the U.S. and Canada, increased its earnings by 25 percent in the first quarter. CBS News financial contributor Mellody Hobson joins "CBS This Morning" from Santa Barbara, California, to discuss why dollar stores are winning over shoppers.