1. HTML5 is a major revision to the HTML standard that is still under development and aims to be the future of the web.
2. It includes new elements like <video>, <audio>, and <canvas> that allow embedding multimedia without plugins, as well as features like geolocation.
3. The HTML5 specification is very large, covering HTML, SVG, CSS, and APIs. It aims to provide a common standard for web applications.
4. HTML5 is not just a marketing term - it represents an ongoing effort to develop a unified standard for the next generation of the web.