Using System Services
Several system-wide services are available, such as the Spotlight search capability (see Chapter 5), the Colors and Fonts panels used by many applications (including Mail and Apple's iWork productivity suite), data detectors, spell-checking and grammatical text services, iCloud Documents storage used by many applications (see Chapter 8), the new Share function (see Chapter 23), and the new notification service.
These services generally don't call attention to themselves as separate entities but become part of the applications that use them, much like how the Open and Save settings sheets or dialog boxes, Print settings sheets or dialog boxes, and Spotlight search boxes provided by OS X appear to be part of the applications that use them. An exception to this “quiet” behavior is the notifications service, which runs on its own and calls attention to its messages as they arrive.
The notifications service is new to OS X Mountain Lion. If you use an iPad, iPhone, or iPod Touch, this feature is familiar to you from the notifications service in iOS 5. Now it's in OS X as well.
Working with notifications
If you've used a prior version of OS X, no doubt you have noticed the new bulleted-list Notifications icon button at the far right of the menu bar. If clicked, it opens the Notification Center that shows you the most recent alerts and updates from a variety of applications and even websites (via the Safari browser). You can also swipe with two fingers ...