The mobile industry is worth some $1.56 trillion. Most of that money comes, of course, from the sale of devices and the data plans that go with them. But a sizeable chunk comes from the proverbial "other" category: companies that neither make nor sell devices, but supply the goods and services that make our mobile lives possible. As speaker, author and cellphone expert Tomi Ahonen puts it, these "interesting side aspects to the industry that relate to phones but are not digital-electronic tech as such" are often overlooked, but they've "morphed" into a megasector of their own—one worth an estimated $125 billion. Here, a few of the many businesses that piggyback on mobile.