Philip Schiller, iPhone maker’s senior vice president of Worldwide Marketing, said, “Just a year after the incredibly successful introduction of Lion, customers have downloaded Mountain Lion over three million times in just four days, making it our most successful release ever.”

Some of the features of Mountain Lion include new Messages app, Notification Center – the feature derived from the iPhone and iPad whereby text messages sent to those devices will also show up on a Mac computer, system-wide Sharing, Facebook integration – this one is going to be provided in the next update to the OS, Dictation, AirPlay Mirroring and Game Center.

Mountain Lion also features a new security tool dubbed Gatekeeper that will help defend against malware. Gatekeeper will be able to fend off malware by controlling application installation.