There is a thread on the DNS problems with the domain here
Currently both domains (www.kmeleon.org and kmeleon.org) are resolving to 184.108.40.206 (down). I have been using kmeleon.sourceforge.net (till recently finding out I can use kmeleon.sf.net) for a long time now. I could guess that the lack of the domains accessibility hurts the browsers popularity and support. I think it would be a good idea to update the DNS records or change the "official domain" with a message on the index page that says "welcome to kmeleon.sf.net" or something.