Previewed at WWDC, launching in the fall.
Websites Begin Supporting Safari Push Notifications Ahead of Mavericks Launch
Push notifications in Mavericks may be a handy alternative to RSS or Twitter for many users, delivering clickable notifications directly to the users' desktops in a timely fashion.
While several sites have already begun to go live with their notification services, accessible to users running the OS X Mavericks beta, others will undoubtedly be following suit as Mavericks officially launches to the public. MacRumors will be supporting the feature, allowing users to receive instant notifications whenever new articles are posted to the site.
OS X Mavericks is expected to launch to the public before the end of the month, but may arrive as soon as this week following the final introduction at tomorrow's media event.