"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," said Philip Schiller, Apple?s senior vice president of Worldwide Marketing.
Mountain Lion launched on the Mac App Store last Wednesday as a $19.99 upgrade from Lion or Snow Leopard. It includes iCloud integration, a new messaging application, Notification Center, system-wide sharing, Facebook integration, Dictation, AirPlay Mirroring and Game Center.
With more than 3 million copies downloaded in the first four days, Mountain Lion marks the most successful OS X launch in Apple's history. Last year, sales of OS X 10.7 Lion topped 1 million in its first day of availability, while total sales had exceeded 6 million by last October.
Customers who bought a new Mac after June 11 are eligible to upgrade to Mountain Lion at no cost.
The first public sign of Mountain Lion's success came last Friday, when Chitika Insights revealed that after just 48 hours of availability, Mountain Lion accounted for 3.2 percent of all Mac Web traffic. In just two days, the total usage of Mountain Lion tracked on the Web neared that of Mac OS X 10.4 Tiger.
For an extensive look at the features and functionality found in Mountain Lion, see AppleInsider's in-depth Inside Mountain Lion series.