The skyline of San Francisco, May 7, 2025. Silicon Valley is again betting everything on a new technology. But the mania is not a reboot of the late-1990s frenzy. (Loren Elliott/The New York Times) By David Streitfeld The dot-com boom, a period of wild exuberance and extreme hype that began in the mid-1990s, built the foundations for the contemporary wired world. When the internet mania turned to bust in March 2000, it made a bit of a mess. The trouble spread from Silicon Valley to the larger...