Notifications are OS X’s chief tool for keeping you on top of things. A notification can alert you to impending Calendar events and reminders, as well as to email, Facebook, and Twitter messages. 

Though it’s new to Mountain Lion, the Notifications feature may look familiar if you’ve been using an iOS device for a while. You’ll have seen such notifications there: banners that pop up on your lock screen to display alerts for Calendar events or let you know that you’ve received text messages. Here are some of the most frequently asked questions about this OS X feature.

Q: What are the things notifications can notify me about?

A: Any application can use notifications, as long as the app hooks into OS X’s Notifications feature. For starters, Apple programs such as Calendar, Reminders, Mail and Messages can display notifications. Many third-party apps also use notifications. For instance, if you have added your Twitter and Facebook logins to Mountain Lion’s Mail, Contacts & Calendars preference pane, you can see status updates and tweets. 

Here’s an alert-type notification. You must click one of the buttons before the alert can disappear.  

On our Macs, we also see notifications from Panic’s FTP application Transmit (£23.99); Red Sweater Software’s blogging tool, MarsEdit (£27.99); and Literature and Latte’s writing tool, Scrivener (£31.99).

Q: Can I control how my notifications look?

A: Choose Finder System Preferences (or click the System Preferences icon in the Dock) and click Notifications. Here you’ll see all your options. Then you can make your decisions on an app-by-app basis; so first select an application from the list on the left, then choose from the three alert display styles: ‘None’, ‘Banners’, and ‘Alerts’. 

‘None’ means you won’t see any notifications. If you are getting too many notifications, go to the Notifications preference pane and choose the ‘None’ alert style for all the applications you don’t need to know about. ‘Banners’ display on your screen for just a few seconds and then disappear. 

Choose this alert style for notifications you want to see when you’re sitting at your Mac, but otherwise don’t care about missing. ‘Alerts,’ like banners, will appear at the top-right of your monitor, but they don’t go away until you act on them. 

You can click the Close button to dismiss the alert, but you can also click the Show button to go to0 the application in question and find out what just happened. 

Q: Can I get more specific about what I get notified about?

A: Yes. If you look closely, you’ll see more options in the Notifications preference pane, but the choices will change depending on which app you have selected. For example, click Calendar and you can choose how many items to show in the Notification Center. 

You can also choose to display information on the app’s icon badge – the little red circle with a number in it on the corner of the icon. You can choose whether to have an alert sound played when a Calendar notification comes in. Click on Twitter in the list, and then click the Notifications button to get even more specific. You can, for instance, determine whether notifications will show mentions and replies from only the people you follow or from anyone.

Q: What is the Notification Center?

A: So far, we’ve been talking about the alerts that display above your other windows, but there’s another place to see your alerts: OS X’s Notification Center, which is a kind of sidebar at the right edge of your screen. Click the right-most icon in your menu bar – the one with the three lines – to display it.

Depending on your settings, different applications can display their notifications here. You can choose whether or not to have an application display an alert, but it can also show its notifications only in the Notification Center. To choose which of your apps are displayed in the Notification Center, you need to scroll through the list on the left side of the Notifications preference pane until you find a divider labelled ‘Not in Notification Center’. Then, drag the apps you want from below that divider to the top section.

You can also choose the order in which apps display. From the bottom of this preference pane, click on the Sort Notification Center menu and choose either ‘By time’ (with the apps that you have most recently received alerts for listed at the top) or ‘Manually’ (in the app order you have specified in the Notifications preference pane).

The Notification Center also offers you a quick and easy way to hop straight to any applications that need your attention. Simply click an item to open the parent application. Click an email notification, for example, and Mail will open to that message. To dismiss notifications in the Notification Center, click the ‘X’ button to the right of an application’s name.

Q: Are there any shortcuts for viewing the Notification Center?

A: One way to view the Notification Center is to swipe from the right side of the trackpad with two fingers to the left. Then swipe to the right to hide the sidebar.

While there are no default keyboard shortcuts to view the Notification Center, you can easily create one if you wish. Go to the Keyboard pane of System Preferences, click the Keyboard Shortcuts tab, and select Mission Control in the left column. You’ll see a Show Notification Center entry. Check the box, double-click the right-most part of its line, and then enter your keyboard shortcut.

We also find it easier to set up a hot corner. With this, we move the cursor to the corner of the screen to show Notification Center. To do this, go to the Mission Control preference pane, click the Hot Corners button, and then click one of the menus to choose Notification Center for the corner you want.

Q: I’m on deadline. Can I turn off notifications for a short time?

A: You can turn off notifications (until the next day) by Option-clicking the Notification Center icon in the menu bar. The icon will go grey. If the Notification Center is visible, scroll down, and a Show Alerts and Banners toggle switch will display; use this to get the same result.