On the down side, people with malicious intent can use this extensive archive to figure out ways to hack the Mac. The fact that this hasn’t happened—like I said above, Darwin has been available for years—is a testament to the integrity of the Apple community.
No, it means that it’s really true that openness leads to better security. In fact, Apple took a lot of their open source code from OpenBSD, a system known for its security focus.
So here are my observations: Mac OS X, and Apple’s development paradigm, is the anti-Linux. And it’s Steve Jobs’ big accomplishment that Apple has built a better (I should actually say “more successful”) Linux than Linus Torvalds has ever been able to do.
This seems to imply that Mac OS X and Linux (or Jobs and Torvalds) have the same goals, which clearly has never been the case.
Edit: It would seem I’m misremembering. It seems Apple leveraged FreeBSD more than OpenBSD. See the comments.