Understanding intrinsic content sizes is absolutely key to taming Auto Layout and Jonathon Mah has a great explanation of how it all works along with code samples and a full project demonstrating the concepts. I'm no big fan of Auto Layout at the best of times but before I learned about intrinsic content sizes, it sometimes felt flat out broken (which it isn't, mostly 😇).
One of the aspects of Swift that made it into the WWDC keynote was the fact that it is faster than Objective-C. There have been several blog posts posted since the language was unveiled showing that it's both faster, and slower 😌. Mike Ash sensibly avoids benchmarks (it's still a beta) and instead concentrates on explaining the reasons that Swift should be faster.
Peter Steinberger with an interesting story of debugging a problem with his Aspects library. It's basically a story of swizzling, and ends with an alternative approach to method replacement.
More custom operator fun from Josh Smith. Apple are obviously concentrating on getting the basics right first of all with Swift but I wonder if they will experiment with anything like this as the language matures?