It’s a boring and predictable answer but I’m going to say mobile phones with a particular reference to the iPhone. I’m not even a fan of Apple products, but the fact remains that when Jobs rst waved that thing around on stage I scoffed and dismissed it as a silly publicity stunt for a vapourware device that would be better suited as Star-Trekian prop. But as PC Authority said when it launched, “It pulls the rug from everything that’s come before it.” That it (for better or worse) has subsequently transformed society in many ways is almost incidental. The fact that I still remember Dave Stephenson’s review of it is probably telling. Also, I was working on PCA at the time.