As you probably know by now, OS X Mountain Lion will include a number of popular apps and features such as Messages, Notes, Reminders, Game Center, Notification Center, Share Sheets, Twitter integration and AirPlay Mirroring from iPad.
Interestingly,9to5Mac has discovered that the updated version of OS X Mountain Lion Developer Preview 3 includes a "Do Not Disturb" toggle for Notifications to hide alerts and banners.
The feature is a toggle accessible at the top of Notification Center that allows users to block incoming alerts and banners. The feature is very important for those who look to focus entirely on the content they are currently working on and do not want to be bothered by new emails, iMessages, calendar alerts, or other types of alerts.
The OS notes that the feature is activated with a moon logo on the top right of the menu bar.
It seems like a nifty little feature. We hope Apple also brings the "Do Not Disturb" toggle for Notifications to iOS as well, as banners and alerts can get quite annoying when you're playing a game or watching a video on your iPhone or iPad.via[iphonehacks & 9to5google]