Another feature combo brought over from iOS involves notifications and the Notification Center. One of the more annoying aspects of OS X is the way applications try to get your attention. Sometimes it's by way of icons jumping in the Dock, other times it's through alert windows. Clearly something better was needed. Although the Growl app attempted to fill the void, displaying customizable alerts for apps that supported it, the Mac platform really needed a systemwide service.
In iOS 3, Apple introduced a push notifications service to handle app messages. Then, in iOS 5, the company organized app messages with the Notification Center, the repository for banner alerts. Since the arrival of iOS 3, 1.5 trillion push notifications have been sent through Apple's servers. Scott Forestall, senior vice president of iOS software at Apple, bragged at WWDC that 7 billion alerts are being processed each and every day. It was inevitable that Apple would add this feature to OS X. With Mountain Lion, notifications are on the Mac.
Like Growl alerts, notifications show up on the upper right part of your screen. As in iOS, these notifications can be customized to appear as banners -- which slide from the menu bar and hang around for a few seconds before slinking off to screen right -- or alerts, which must be manually dismissed.
The Notifications preferences panel is where users select which apps use the feature and decide how alerts should be displayed on-screen.
To the absolute right of the menu bar, in the spot previously occupied by Spotlight, is the icon representing the new Notification Area. Pressing this button, or swiping on a trackpad from right to left with two fingers, reveals an area hidden "under" the desktop where recent notifications are stored.
From here, you can view all system and application notifications, and even compose tweets -- as long as the Share button has been enabled in the Notifications preferences panel. (Facebook integration is coming this fall, no doubt in tandem with iOS 6, which will also get this feature.)
In the lower right of the Notifications area is a small icon that launches the Notifications preferences panel, so you can customize how individual app notifications behave. As in iOS, you have a few options: You decide whether notifications should show up as banners, alerts or not at all; you pick the number of recent items you want to see displayed; you decide whether alerts should also display badges on an app icon; and you determine whether sounds should play when notifications arrive. And there may be app-specific options as well.
One of the most embarrassing aspects of giving presentations is the fact that your life can unexpectedly pop up on-screen for all to see if you're not careful. Thankfully, notifications can be turned off right from the Notification Center: Scroll up and you'll see the option to toggle it on/off. Or you can hold down the Option key while clicking the Notifications icon in the menu bar. Even better: When you connect your Mac to a projector, Notification Center turns off automatically.
The Notification Center in Mountain Lion works better than it does in iOS, simply because the onscreen elements are perfectly sized for mouse clicks. It sometimes takes a lot of taps to hit the X to close in the iOS version. But the Notification Center in OS X doesn't display widgets like weather and stocks as it does in iOS. (They're still limited to the Dashboard.) Apple could make the Notification Center even more robust in the future by adding information from widgets and perhaps consolidating download and file transfer progress information.