Hi, not sure if it has been mentioned somewhere already, but the Proceedings of the National Academy of Sciences of the United States of America (aka PNAS) has a paper on the evolution of software in Debian. http://www.pnas.org/content/early/2011/11/14/1115960108.abstract Unfortunately not open-access, but arxiv.org has the PDF http://arxiv.org/pdf/1111.5251 Michael -- Michael Hanke http://mih.voxindeserto.de