Mac OS X Yosemite has a notifications center just like older versions of the operating system, but with Yosemite, Apple is adding extensions to allow you to get notifications about what you want. There will also be third-party extensions for the Notification center available from the app store. Here’s how to tweak your Notification Center in Yosemite.
1. Open your notifications by clicking on the bulleted list icon in the upper right corner of the screen.
2. Click on the “Edit” button.
3. Drag an item to change the order.
4. In the Items list on the right, choose extensions you want to add and click on the green plus icon to add them to your Notifications.
5. Click on the “App Store” button to see third-party extensions for sale.
6. Click Done when you’re finished.