Though the biggest news around Apple's newest operating system for Mac is its "free-ness," Apple's Craig Federighi gave a demonstration on new and useful features. For starters, notifications including emails and messages appear in a small window as they are delivered. Users are able to reply to the message directly through the notification window without having to ever maneuver away from their current task. Third-party application notifications can appear in the same way, but are controlled by the user in the notification center. Tags for easy categorization are now available for pictures and documents. The built-in Calendar app will auto-fill with location and weather information for each scheduled event, and the Map app is able to send directions with a single click from a Mac or MacBook to an iPad or iPhone. All content users store on an iPhone, iPad, MacBook or Mac will now automatically appear on all other personal Apple devices, letting a user begin a project on a MacBook and continue it on the morning train from his or her iPad.