The CMS Matrix : CMSmatrix lets you easily compare the features in over 1200 content management system products. Check the boxes next to the software you're interested...
When can I use... : Compatibility tables for support of HTML5, CSS3, SVG and more in desktop and mobile browsers.
AppJS : Build Desktop Applications for Linux, Mac and Windows using HTML, CSS and Javascript
WebPlatform.org : Web Platform Docs is a community-driven site that aims to become a comprehensive and authoritative source for web developer documentation.
GateOne : Gate One is an HTML5-powered terminal emulator and SSH client