HTML5 is the upcoming revision of the HTML standard, offering new features such as video playback and drag-and-drop functionality that previously required third-party plugins. The specification, led by Ian Hickson of Google, is in draft form and expected to evolve further, with stable parts already available for implementation. While HTML5 enhances web capabilities, it does not fully replace existing technologies like Flash or Silverlight, as some functionalities still require commercial enhancements.