CloudBasedIDE
ThoughtStorms Wiki
An IDE delivered over the web that runs in TheBrowser and allows SocialCoding
ProgrammingWithAndInWiki should be this.
Makes it easier to make AGoodIDE
Examples :
WebContainers let you run a virtual server inside the browser. (Basically you download your entire server environment as a virtual machine to run locally in the browser)
BespinEditor was the original attempt at one.
See also :