Mac OS 9 is the final major release of Apple's Classic Mac OS operating system. Introduced on October 23, 1999, Apple positioned it as "The Best Internet Operating System Ever," highlighting Sherlock 2's Internet search capabilities, integration with Apple's free online services known as iTools and improved Open Transport networking. While Mac OS 9 lacks protected memory and full pre-emptive multitasking, lasting improvements include the introduction of an automated Software Update engine and support for multiple users.
Apple discontinued development of Mac OS 9 in 2002, transitioning all future development to OS X. Since that time, no updates have been released. The final updates to Mac OS 9 addressed compatibility issues with OS X while running in the Classic Environment and compatibility with Carbon applications. At the 2002 World Wide Developers Conference, Steve Jobs began his keynote address by staging a mock funeral for OS 9. However, there are still users of Mac OS 9 today. Specifically retro-gamers, people using old software that was discontinued before the introduction of OS X or users of old hardware incompatible with OS X. (PowerPC Macs made before the introduction of the G3 processor.)
Apple billed Mac OS 9 as including "50 New Features" and heavily marketed its Sherlock 2 software, which introduced a 'channels' feature for searching different online resources and introduced a QuickTime-like metallic appearance. Mac OS 9 also featured integrated support for Apple’s suite of Internet services known as iTools (later re-branded as .Mac, then MobileMe, which is now known as iCloud) and included improved TCP/IP functionality with Open Transport 2.5.