Mark Shuttleworth, the founder of Ubuntu Linux, has explained why he thinks the DCC (Debian Common Core, but don't let the Debian guys hear that) will fail. "The vision behind DCC, which is indeed compelling, is that it would provide a common platform for certification, and that the distros that make up the DCC would all ship exactly that same core. But it strikes me that this approach has never worked in the past. In fact, every distro ALWAYS modifies elements of the core, and with good reason. And while we would love that not to be the case, the truth is that the reasons to specialise outweigh the benefits of homogeneity."