I worked at Apple on OS X server in various capacities for a few years, and really loved the experience. As an open-source user and advocate, I was really sad there because they have a very hostile and defensive position about open source (which is a very reasonable stance, in my perspective).

The fact that there aren't any prolific bloggers, open source contributors or HN commentators is an artifact that the company does not encourage anyone to do that -- in fact, they actively discourage anyone that isn't involved in open source work on Webkit or Obj-C or Swift from talking about their work. For better or worse, they still have a culture of secrecy around their products.

For what it's worth, I really enjoyed my time there and wouldn't trade it for anything else; I worked with a lot of fabulous teams, learned a lot, and got to build some really amazing stuff.