No matter how different the technology, the people who are using it haven’t changed. And most usability principles have more to do with human capabilities and limitations than with technology. (Examples of such eternal design principles discussed in this article include error prevention, flexibility, efficiency, visibility of system status, and recognition vs. recall.) The Echo offers unique value, even to users who already own good voice-interaction systems. Although the medium of voice is quite different, both the frustrating errors and the seemingly magical success moments experienced when using the Echo can be clearly traced to tried-and-true usability heuristics.