Apple’s Public Mailing Lists

You may not be aware but Apple has a pretty extensive set of public e-mail discussion lists.

https://lists.apple.com/mailman/listinfo

There are topics ranging from fundamental Objective-C issues through to development for their various desktop applications.  Some of the lists are quite chatty but you can subscribe in digest format to get a daily e-mail instead of each individual message.  This is a great way to reach engineers working on the piece you’re interested in and is a quite interesting place to lurk.