Whether you're a designer or a developer, if your job requires you to do anything with graphics, you've got to check out Xscope.
Apple didn't just slap a humongous display on its latest handset: It also made a lot of smart design and technology decisions to make that screen make sense for end-users.
One of iOS 8's coolest new under-the-hood technologies, extensions will allow apps to share functionality with each other, which could make those apps both easier to use and more powerful than ever.
The company's new mobile operating system will come preinstalled on new iPhones and be available as a free updates for existing users.
They may not be as exciting as a new handset or wearable technologies, but extensions could well be iOS 8 and OS X Yosemite's star feature.
As the recent celebrity photo breach has shown, security is a tricky business, but Apple is uniquely equipped to tackle it.