EarthLink, now merged with Mindspring, is the second largest ISP in the US, behind AOL but ahead of MSN. Apple has invested $200 million in EarthLink and partnered with them to make EarthLink the default ISP for new Macs inside the Internet control panel. Now, every Mac user that signs up with EarthLink earns Apple some money. Apple also gets a seat on EarthLink's board.
The big crowd pleaser of the keynote was Jobs announcement of Mac OS X, its structure, its "Aqua" look and its new Finder. OS X should be released sometime this summer and will be in all shipped machines by January or so.
Mac OS X will feature a modern open source Mach micro-kernel, preemptive multitasking, multi-threading as well as many other features Mac users have been waiting for over the past decade. Mac OS X includes three main APIs. The classic Mac API from OS 9 lets older applications run but doesn't give them all the great features of OS X. The Carbon API is an interim step for developers to port OS 9 applications to. Applications can be quickly ported to Carbon and by doing so will gain most of OS X's features. The Cocoa API is the full Mac OS X API. It enables a program to take full advantage of OS X's features.
Another interesting detail of OS X's design is its Quartz 2D drawing system. Essentially, Quartz uses Adobe's PDF format as Mac OS X's native 2D drawing system. In addition to enabling blazing fast PDF loading and redrawing as well as excellent compatibility over the Internet, Quartz gives an impressively feature packed 2D drawing system to every Mac OS X application. Jobs showed off transparency and automatic anti-aliasing during his keynote. Apple's use of the PDF format for OS X strongly resembles NeXT's use of Adobe's Display Postscript in the NeXT OS.