As a former Apple employee, I know just how seriously Apple takes its secrets. Even today, years after my NDA has expired, I'm reluctant to talk about things that Apple flagged as confidential. One reason for that reluctance is because of the respect I have for the company and my friends who still work there, but of course another part of it is I don't want to make anybody there angry.
But not all past employees are like me. And over at Quora there's a very interesting thread where past Apple employees talk about what it takes to keep the company's secrets. Interested readers should check out the thread in its entirety, but here's one of my favorites (this from an anonymous Apple employee):
All prototypes are laser marked with serial numbers and tracked by a central tracking system (called iTrack). Physical security is also highly prioritized, with prototypes required to be locked up when not in use. Access to prototypes is also restricted, and the default assumption within the company is that your coworkers do not know what you're working on.
Physical access to the areas of certain groups (product design, industrial design and reliability) is highly restricted by badge access. The most sensitive areas, such as the Industrial Design Studio, have receptionists, external cameras to screen guests, and require an escort to vouch for you. Within these areas and groups, knowledge of the product pipeline and access to prototypes is widespread, but that knowledge doesn't leave the group.
And here's a rather humorous story that puts Apple's secrecy in perspective. This is from Adam Banks, editor of MacUser UK in the late 1990s:
I was editing MacUser (UK) in 1998 when rumours surfaced that Apple was working on a completely new kind of Mac. By a series of flukes, we became the first magazine to print what turned out to be a pretty accurate description of the machine a couple of months ahead of its launch as the iMac. We got the details from someone who worked at a third-party site where Apple had seeded a test unit.
Probably safe by now to mention what the site was. It was the Pentagon. Compared to the real secrets they were keeping, when it came to some plastic PC they'd been asked not to talk about, I suspect nobody gave a shit.