. What made that preview unique was that very few new features were shown--and Apple admitted that new features weren't the focus of Snow Leopard. Instead, Snow Leopard centers around the performance of OS X, quality improvements, and setting the stage for future OS X innovation. Bertrand Serlet, Apple's senior vice president of Software Engineering, said at the time, "In our continued effort to deliver the best user experience, we hit the pause button on new features to focus on perfecting the world's most advanced operating system." This means that Snow Leopard will be unlike any other major OS X release in that features won't be the primary selling point. That doesn't mean, of course, absolutely no new features.

As of now, however, Apple has disclosed only five new features for , two of which will be immediately apparent to the typical user. First, Snow Leopard gains native support for Microsoft Exchange 2007 in Mail, Address Book, and iCal. So users with employers who rely on Exchange will, for the first time, get full out-of-the-box compatibility for their e-mail, contacts, and calendars.

The second end-user features relates to QuickTime. In Snow Leopard, QuickTime gets a major revision and a nifty new name to match: QuickTime X. Beyond the new moniker, however, we know very little about what's new in QuickTime X. Apple states only that QuickTime X is "a streamlined, next-generation platform that advances modern media and Internet standards. QuickTime X features optimized support for modern codecs and more efficient media playback, making it ideal for any application that needs to play media content."

As for the other three new features Apple has revealed, most end users won't immediately them. Still, they're very important for the future of the operating system. First, Snow Leopard uses its 64-bit architecture to extend the software limit on system memory up to 16 terabytes. To put that in perspective, that's more RAM than today's 32GB limit. And--unless new Mac Pros come out with 4,000 RAM slots--it's a purely theoretical limit. The largest RAM chips currently available are 4GB in size, meaning that 32GB will remain the practical memory limit (in an eight-slot Mac Pro) until larger RAM chips are released. But when such chips are available, Snow Leopard will be ready for them.