Canonical did the same thing with Launchpad for five years before finally releasing the whole thing, including the build system (which was expected to be kept proprietary).
Heh. Yes, in the very early days of Canonical I chatted with Mark about the possibility of working there and that intention to closely hold some of the software I'd be working on was one of the red flags for me. In my view, it was partly because Canonical went down that path that GNU Arch got forked and horked (mainly by Canonical employees).
