Society for Commercial Archeology  The Society for Commercial Archeology (SCA) is an organization based in Wisconsin, United States. It is the oldest national organization devoted to the buildings, artifacts, structures, signs, and symbols of the 20th-century commercial landscape. The SCA activities include publications, conferences, and tours to help preserve, document, and celebrate the structures and architecture of the 20th century, including diners, highways, gas stations, drive-in theaters, bus stations, tourist courts, neon signs.