Simply the clearest and best explanation of ARC that I have seen so far. Fascinating.
More ARC, this time from Jiva DeVoe who has been looking into ARC and exceptions.
Ole Begemann on saving significant amounts of memory loading images if you just need to get at the metadata.
This week seems to be image performance techniques week as Oliver Drobnik takes a look at image loading performance. I never thought to run pngcrush on the server, clever.
Jamie Montgomerie with a fascinating bit of internet archaeology digging into modern syntax for Objective-C. An old post but it came up this week after a discussion at the NSScotland conference (which was excellent!).