Problems updating itunes and quicktime
It was completely redesigned featuring a 3D Dock, a new purple color scheme, and over 200 new features.
So, for example, if your domain name were widgets.com, your incoming mail server would be mail.3.
Due to many problems and complaints about Cheetah, Apple directly got to work on releasing Puma, the next big cat in Mac OS X. Apple gave 10.0 users a free Mac OS X v10.1 install CD to make up for the flawed operating system before.
As of January 7, 2002, Apple said Mac OS 9 and other previous operating systems from Apple were "going in the computer scrapyard" by the end of the month (January 31, 2002) and OS X would be the default and only operating system available on all Macs.
Snow Leopard dropped support for Power PC Macs too.
OS X Lion was first shown to the public at the "Back to The Mac" event in 2010, announced more at WWDC 2011, and released on July 20, 2011.