The HTML Standard is a kitchen sink full of technologies for the web. It includes the core markup language for the web, HTML, as well as numerous APIs like Web Sockets, Web Workers, localStorage, etc.
This document explains the syntax, vocabulary and the available APIs for HTML5 documents, focussing on simplicity and practical applications for beginners while also providing in depth information for more advanced web developers.
W3C Semantic Web group's webapp implementation of pyRDFa: parse RDFa from a URL, uploaded file, or text area; get bookmarklets to parse RDFa directly from the current page.
D. Huynh, D. Karger, and R. Miller. Proceedings of the 16th international conference on World Wide Web, page 737--746. Banff, Alberta, Canada, ACM, (2007)