The Apple fabric everywhere
If there's one lesson from WWDC's announcements, it's that Apple is building a federated computing and content fabric intended to blanket you where you are. Former CEO Steve Jobs suggested as much in 2010, and each version of iOS and OS X has pushed the Mac, iPhone, and iPad closer together. This fall's iOS 7 and OS X Mavericks (named after a California surfing beach) get even closer, with Apple Maps and iBooks jumping from iOS to OS X, iOS notifications now pushed to OS X, notifications states synchronized across all devices (if you dismiss one on one device, it's dismissed on all), and iCloud syncing passwords and credit card information across Safari on all your devices (a major win for those of us who have to remember arcane passwords across multiple devices, and a real blow to third-party password managers like 1Password).
The federation works deeply in some cases, such as the ability to share a map from your Mac to your iPhone and have the iPhone begin navigation immediately. In other cases, it's more subtle, such as having the Photos app in iOS adopt a more visually rich version of the Events approach to photo organization in Photos for OS X. The new MacBook Airs that boast 12 hours of battery life, using Intel's new "Haswell" chip, also reflects that federation: A MacBook Air now can run as long as an iPad on a single charge, blurring the lines between tablet and laptop computing even more, in what I suspect Apple wants to become a greater "and" usage of the two, not an "or" choice between them.
In some cases, the federation is unclear: iOS gets OS X's AirDrop feature, which allows drag-and-drop file sharing among recent Macs; in iOS, you use the Share sheet to send content to one or more friends on the same Wi-Fi or Bluetooth network (they have to explicitly accept the encrypted documents, and can hide themselves from sharing). It's unclear whether AirDrop allows document sharing between Macs and iOS devices, which third-party utilities like GoodReader have done for years. Another case of potentially missing integration is Passbooks, Apple's service for e-tickets, cards, and potentially mobile payments on the iPhone; it got no mention at WWDC.
The federation works in your car -- or it will in most car makers' models beginning in 2014, if Apple is to be believed. Last year, Apple announced Siri Eyes Free, essentially the integration of Siri with a car's microphone and Bluetooth to control your iPhone and perhaps built-in car navigation. Of course, if you have to use your iPhone, it's not really eyes-free and probably not hands-free.
Little has happened since, but Apple showed off at WWDC yesterday a car stereo that displayed the iPhone's screen and used Siri. Details are scarce, but the notion is that the iPhone's screen mirrors to the car's built-in navigation system's screen, à la AirPlay Mirroring. That's not eyes-free, but it is as hands-free as a built-in nav system, with the advantage of using apps and gestures you already know from your iPhone and being Siri-controlled. "Car-safe" apps such as music and navigation will now work in your car as they do on your iPhone.