For example, they will sync up with your iPhone and iPad, so that the same notifications you’d be getting on your mobile device will be popping up in a corner of the screen of your MacBook or iMac. You’ll even be able to click on them to quickly respond, which means Facebook flame wars with your out-of-state relatives are about to go to a whole new level of intensity. You know those notifications that pop up on your phone when (depending on your settings) you get a text message, or an alert from Facebook, Twitter, Words With Friends, or any of countless other apps that “push” notifications to your phone without you having to open their apps to see it? OS X has had them since its last version, but in Mavericks, they’re getting an upgrade. Apple Let’s just hope push notifications from websites don’t become a new kind of spam.