I took a look at this project 2 ish years ago. They just weren't quite up to snuff. But I think their real problem is that google/google apps came along and stole their momentum. Chandler was designed as an exchange killer, but google seems to have done a better and quicker job. RMS's dislike of the 'cloud' aside, why bother hosting your own services if you don't really need to? I wonder if procmail kind of went this direction as well. How many folks are still hosting their own user email systems?