Recent versions of Mac OS X provide a Notification Center, which allows applications to display notifications when something happens. Many people don't realize that websites are also allowed to send you notifications! When you visit a site that uses Mac OS X Notifications, you will see something like this:
If you click the Allow button, or press return (which could happen without the user realizing what has happened), Mac OS X will begin showing notifications whenever that website sends them. Notifications may show a banner, which appears in the upper right corner of your screen and looks like this:
(This image is from Apple's documentation on creating website notifications, and is used as an example, not because it is a real notification.)
If you are having annoying banners like that showing up, you have probably approved a request by a website to show notifications. To remove these notifications:
- Launch Safari
- Click Safari from the menu, then Preferences
- Click Notifications. You should see this:
- Set the option to Deny for any websites that you do not want to receive notifications from.