- Messages - new version of iChat with iMessage support.

- Reminders - create lists and tasks, synced via iCloud.

- Notes - create notes, synced via iCloud.

- Notification Center - on screen pop-up notifications.

- Share Sheets - share buttons to email, tweet, message, etc...

- Game Center - social gaming center for Mac.

- AirPlay Mirroring - broadcast your Mac's screen to your Apple TV