In OS X Mountain Lion, Apple has split Notes off from Mail as its own app, mirroring iOS. Additionally, Mail gets new VIP contact, notification and search features, while the all new Notes app for OS X provides a new option for drafting ideas that are kept up to date across all your devices via iCloud.
In OS X Mountain Lion, Apple has replaced iCal with two separate Calendar and Reminders apps, harmonizing with iOS and improving the overall interface while making Reminders not just calendar event with alarms, but also location-based notifications.
In OS X Mountain Lion, Apple has replaced Address Book with Contacts, bringing the simpler OS naming convention to OS X and adding a variety of new improvements, including easy sharing, card linking between different accounts and (later this year) Facebook integration.
In OS X Mountain Lion, iCloud begins to take shape as the smart, automated way to store documents on a per-app, device independent basis, incrementally displacing the local file system that non-technical users have long struggled to comprehend and replacing it with a cloud-based service that connects and synchronizes desktop and mobile devices via the Internet.
In OS X Mountain Lion, Apple is radically improving the layout of Universal Access features for users who are sight, hearing or motor impaired, and changing the name of its portfolio of features to match iOS: "Accessibility."
Apple is expanding Game Center from an iOS play into the Mac arena with OS X Mountain Lion, enabling developers to add friend requests, recommendations and challenges as well as unlockable achievements and top score listings.
AirPlay, Apple's wireless audio and video distribution system, gets an update in OS X Mountain Lion, offering modern Macs with compatible hardware the ability to wirelessly mirror the screen to an Apple TV-attached HDTV display.
In Mountain Lion, Macs are getting system-wide speech recognition, the same "Dictation" feature Apple gave the new iPad at the beginning of the year. While it works well, it does require a network connection.
Safari turns 6 in this summer's release of OS X Mountain Lion, offering a new view of open tabs similar to iPad and a new iCloud tab-sharing feature, along with an offline Reading List, new website passwords browser, new privacy settings, and a feature that allows websites to send alerts to the new Notification Center.
The new Notification Center service of OS X Mountain Lion, a feature borrowed from iOS, goes beyond its mobile sibling to offer a direct way to send tweets from the desktop. It does not however have iOS 5's live ticker updates for widgets such as Weather and Stocks, something OS X presents in Dashboard instead.
Apple on Monday seeded what is intended to be the final test version of its OS X 10.8 Mountain Lion to developers with no known issues, meaning that the next-generation operating system is all but complete and set for imminent launch.
It was revealed on Monday that Apple's upcoming OS X Mountain Lion will feature an automatic security check feature that will ensure users have the most up-to-date software protection amid a growing number of Mac-targeted malware.