It’s not a lucky quirk of the laws that keeps Amazon from charging you sales tax—it’s a concerted campaign. Former employees tell the Wall Street Journal that the company goes to great lengths to shield customers from the tax man. Employees for example must consult a color-coded map before traveling, and get special permission before visiting a red-colored state, lest they accidentally trigger laws requiring the company to collect taxes.
Amazon is also currently fighting legal battles against nine states that have passed laws to force online retailers to pay up. In the past, Jeff Bezos has said he thought long and hard about sales tax when founding the company, even contemplating putting its headquarters on an Indian reservation. But the company now says sales tax has little effect on its sales, and notes that it’s long advocated a national sales tax for online retailers, instead of a patchwork of state ones.