Alerts, alarms, reminders, email—chances are you see a steady stream every day. Notification Center has become OS X’s Grand Central Station for the information competing for your attention. Its settings control which apps can post messages to the upper-right corner of your display, as well as how those messages look. And the Notification Center sidebar, which slides in from the right of your screen, gives you an overview of it all.
El Capitan continues to refine the big improvements to Notification Center that Yosemite added ①.
① Notification Center’s Today view gives you an overview of the day. El Capitan adds the Find My Friends widget to help you keep tabs on friends and family members’ whereabouts.
Control Notifications’ Look
Individual notifications appear at the top-right of your screen. You can tweak how they appear, or whether they appear at all, on an app-by-app basis.
Go to System Preferences > Notifications and look at the list on the left. This is all the apps that create notifications. Select an app in the list and choose from three notification display styles: None, Banners, and Alerts ②:
② Choose a notification display styles—None, Banners, or Alerts.
None: Pick None and you won’t see any notifications from that app. If you’re tired of Dropbox telling you every time a shared file has been changed, for example, this might be the setting for you.
Banners: Banners display on your screen for a few seconds and then disappear. Select this type of alert when you don’t mind missing an app’s notifications. For example, you might like to know when Mail messages arrive but not mind if you miss a notification when you walk away from your desk.
Alerts: Alerts don’t go away until you do something. Use this alert style for notifications you can’t miss. For instance, click Close to dismiss a Calendar alert or Snooze to dismiss it for 15 minutes ③.
③ An alert-style notification won’t disappear until you take action.
Reminders’ notifications are even more persistent. You either must click Complete or click Later and choose when to be reminded again.
Turn Off Notifications Temporarily
When you need to concentrate, it can be annoying to see notifications. Option-click the Notification Center icon at the far right of the menu bar to mute notifications until tomorrow. The menu bar icon goes gray. All notifications, including phone calls, are held.
Option-click again to unmute Notifications right away.
Designate Quiet Time
You can set certain hours as regular notifications-free time, too. Go to System Preferences > Notifications and select Do Not Disturb in the list. At the right, check the box next to the first pop-up menu and then choose what hours you want quiet, for example, From: 10 PM To: 7 AM ⑤.
⑤ Tweak Notification Center’s Do Not Disturb settings to ensure you don’t get bugged during certain times (like when you’re studying).
This can be useful if you like to watch movies (distraction-free) on your laptop before bed, or if you don’t want notifications to bother you when you’re taking notes in class. By default, Notification Center turns off notifications when your display is asleep or when you’re mirroring to TVs and projectors. You can adjust these settings, too.
El Capitan forbids calls when Do Not Disturb is activated. However, you can turn that feature off, or select Allow Repeated Calls to let a persistent caller to reach you if he or she calls twice within 3 minutes.
Explore the Sidebar
To reveal the Notification Center sidebar, click its icon in the menu bar. Notification Center slides in from the edge of your screen, covering part of the Desktop. If you use a trackpad, you can use two fingers to swipe from the right side to the left to reveal the sidebar or swipe back toward the right to hide it.
The sidebar has two views: Notifications view (next) and Today view (flip ahead to Check Out Today View).
What to Do in Notifications View
Click the Notifications button to see all notifications that you haven’t taken action on ⑥. Clicking a notification will open its app; for example, click a notification from Messages and you’ll jump straight to the message in the app.
⑥ The Notifications view keeps track of all notifications you haven’t taken action on yet.
Set Up Notifications View
Control what appears where in Notification Center in System Preferences > Notifications. You’ll see a list of app names to the left.
New! Sort Notifications
Choose an option in the Notification Center Sort Order pop-up menu at the bottom of the Notifications pane ⑦:
⑦ El Capitan includes new ways to sort notifications in the Notification Center.
Recents: Choose Recents and only the most recent notifications will appear, sorted by the time they arrived.
Recents by App: Notifications appear in order of most to least recent, grouped by app.
Manually by App: When you choose this option, you can determine the order apps will appear in the Notifications sidebar. In the Notifications pane, drag and drop the app names in the list into the right place.
Seeing a Preview
If you receive a Mail or Messages message, it’s possible to see a preview in the notification ⑧. Click on the app in the list at the left and then choose one of two options in the Show Message Preview pop-up menu:
⑧ You can choose whether message previews appear in your notifications.
When Unlocked: To add a smidge of privacy, previews show only when you’re logged in to your user account.
Uncheck the option if you’d rather previews not appear at all.
Stop Seeing Certain Apps
Select an app in the list at the left. If you don’t want to see it in the Notification Center, deselect the Show in Notification Center checkbox.
Controlling the Number
To control how many notifications you see from it, adjust the Show in Notification Center pop-up menu. The default number of recent notifications is five, but you can go all the way up to twenty.
Check Out Today View
Click the Today button to see Today view. It gives you an at-a-glance overview of what’s coming up, such as when your next meeting is and how many events you’ve scheduled ⑩.
⑩ Look in Today view for a summary of what’s happening. (Top of Today view shown here.)
Items in this view, called widgets, provide access to information or tools. For instance, the Weather widget shows the current weather, the Calculator widget lets you perform simple calculations, and the iTunes widget gives quick access to music controls.
Most widgets are self-explanatory, except perhaps Social. It gives you a quick way to send status updates to social networking accounts, including Facebook, Twitter, and LinkedIn. It also lets you send chat messages via the Messages app.
El Capitan provides a Find My Friends widget. Use it to see the current locations of friends and family (who’ve agreed to share their locations with you) on a miniature map ⑪.
⑪ The Find My Friends widget is new in El Capitan. (Bottom of Today view shown here.)
Customize Today View
The fun part is that you can customize Today view. Drag and drop widgets (click and hold the header) into the order you prefer when you’re looking at Notification Center.
Or, for more options, click the Edit button at the bottom of Today view to switch to Edit mode.
Adding a Widget
In Edit mode, a new column appears at the right with a list of available widgets, such as Calculator, Find My Friends, Social, Stocks, and iTunes. Click the plus button next to a widget’s name to add it ⑫.
⑫ Click Today view’s Edit button to reveal an additional column with more widgets. Click a plus or minus button to add or subtract a widget from your view.
Removing a Widget
In Edit mode, a minus button appears next to the name of each widget already in your view. To remove a widget, click its minus button.
Re-arranging Widgets
In Edit mode, drag and drop them in the left column to control the order in which they appear. Then click Done.
Note that the Tomorrow widget can’t be moved. It always appears at the bottom of Today view.
Configuring Widgets
Many widgets can be configured (and aren’t worth much until you do).
Hover over a widget’s name in Today view and click the info button if it appears. For example, you might want to see the weather not only in your town, but also in your favorite vacation spot. (We can all dream.) Or, you might you want to track the time in your biggest client’s city in addition to your own.
icon at the far right of the menu bar to mute notifications until tomorrow. The menu bar icon goes gray. All notifications, including phone calls, are held.
button next to a widget’s name to add it ⑫.
button appears next to the name of each widget already in your view. To remove a widget, click its minus 
button if it appears. For example, you might want to see the weather not only in your town, but also in your favorite vacation spot. (We can all dream.) Or, you might you want to track the time in your biggest client’s city in addition to your own.