The stock market took a stunning nosedive on Wednesday, with the S&P 500 and NASDAQ experiencing their largest single-day losses in nearly two years. The decline was led by the same big Tech names that had fueled the market's rally this year. The Dow lost a whopping 1.9%, the S&P 500 plunged 2.3%, and the tech-heavy NASDAQ nosedived more than 3.6%. What's behind this dramatic shift, and what does it mean for investors and the future of technology?