People have been selling items in exchange for currency since 200 B.C. when the Roman Empire first introduced currency to the world. It nicely demonstrates how sales have evolved from direct sales all the way to mobile commerce. It’s nice to see how sales have evolved throughout the years. Although some sales techniques are slowly going away, we are seeing the rise of others like mobile commerce. I’m pretty sure we all have bought from at least one of these selling techniques and will continue to buy more.