Lightzone was once a major contender for the top spot among Raw editors, but at some point in 2011 things went a bit awry and the company had to shut down. PDN Puls has the rest of the story:
"It has become an open-source project under a BSD license from creator Fabio Riccardi, who is currently with Apple’s iOS Imaging Group. Under the terms of the BSD agreement LightZone will be offered to the public through the LightZoneProject (www.lightzoneproject.org) free of charge. The software is newly available to the public for free downloading in the Windows and Linux operating systems, and MAC beta testing has begun today. It is also available to the open-source community for new development now."