The document discusses new elements and syntax in HTML5 for building web pages. It covers using the <!DOCTYPE html> declaration, specifying character encodings and languages, including <script> and <style> elements, and bringing back semantic HTML tags like <b>, <i>, and <abbr>. It also discusses new structural elements like <header>, <nav>, <section>, <article>, <aside>, and <footer>. Finally, it covers other new features in HTML5 like figures, details, drag and drop, and microformats.