The posting dated 03/08/2007 announces the takeover by Aptana, and that Aptana has currently setup a forum for the transition.
Radrails was an IDE for Ruby on Rails with a foundation on Eclipse. It combined the ability to create an entire Ruby on Rails project, link it with a CVS/Subversion repository though Subclipse, and create Mongrel/Webrick instances with a few clicks.
Update: Radrails now redirects to an Aptana site. A notice was posted earlier stating that the move accidentally coincided with Radrails’ DNS servers going down at the same time. In any case, an archived version of the old site is still available and archived by Aptana. A roadmap of future development is also up, and the Radrails IDE is up for download once again.