On his wife's birthday last year, Vijay Chetty asked himself: Why can't all mail be digital? And why do businesses spend $1.6 trillion on direct-mail campaigns, most of which end up unread in landfills? His answer is Zipinmail: By assigning a cloud-based mailbox to every residential, commercial, and P.O. Box., it will cut marketers' mailing costs by 90% and save 400 million trees every year. We talk about the huge potential upside for crowdfund investors, his first impressions of America as a student in Alabama, and achieving what has eluded the Postal Service for decades.