Apple is working towards the summer release of OS X 10.8, aka Mountain Lion, and to that end it's released a 2nd Developer Preview to, well, developers. The change log shows that there are still a lot of unfinished edges in the OS, from Game Center to AirPlay to the Notes app. However, one thing you wouldn't know until you ran it is that there's a new privacy feature. Dustin Curtis discovered that when an app attempts to access your contacts, OS X pops up a dialog box asking your permission. Once you grant it, there's a new section in the Security preferences that lists all the apps you've granted permission to.
Obviously, the feature is a response to the privacy issues that were raised last month with iOS, which allows any app to access contact information without permission. Apple promised that it would release an update to iOS that would require explicit permission, but made no such promise for OS X. Desktop operating systems typically offer a much wider array of permissions to apps, though Apple is taking steps to lock that down a bit in Mountain Lion. App sandboxing is one step, and now this permissions dialog is another. As for iOS, Apple hasn't yet said which version would implement the contact permissions dialog, but it wasn't in the iOS 5.1 version the company released on March 7th.