Gobby is a free collaborative editor based on libobby, a library which provides synced document buffers. It supports multiple documents in one session and a multi-user chat. It runs on Microsoft Windows, Mac OS X, Linux and other Unix-like platforms.
The OpenLaszlo platform allows developers to create applications with the rich user interface capabilities of desktop client software and the instantaneous no-download Web deployment of HTML.
These bookmarklets let you see how a web page is coded without digging through the source, debug problems in web pages quickly, and experiment with CSS or JS without editing the actual page.