The cottage door was the people's door. A door for the regular Joe, "the bone and sinew of the land." (That last one comes from the writings of the snooty yet influential 19th-century tastemaker A.J. Downing.) Metaphors aside, the cottage door was indeed designed for America's working class. Constructed of wood stiles and rails, with entry-brightening glass in the upper portion and carved moldings and decorative appliqués in the lower, it dressed up the exteriors of the most modest Italianate, Queen Anne, and Stick houses of the late 1800s.
Cottage doors still hang in front entries nationwide, but my money's on New Orleans for having the most per square mile. That's where durable cypress doors decorate the facades of thousands of shotgun cottages—and salvage yards are chock-full of the castoffs.