The biggest new feature in Snow Leopard is support for Exchange, Microsoft’s popular e-mail, contact, and calendar server.
Apple’s not trumpeting the feature, but Snow Leopard does actually include a certain degree of built-in protection against dangerous software.
Exposé displays one app's windows, including two minimized ones.
Snow Leopard brings a few minor improvements to the Dock.
The Finder, the central point for managing files and folders in Mac OS X, has been completely rewritten in Snow Leopard. But you’d hardly know it from looking.
If you use external hard drives, thumbdrives, or the like, you’ve probably run into one OS X’s annoyances: sometimes your Mac just loves your external volumes so much that it won't let them go. If you’ve ever tried to eject a volume only to have OS X tell you the volume is in use and can’t be ejected, or if you’ve ever been scolded by OS X for disconnecting a volume that was still mounted, you know what we’re talking about.
Many programs autocorrect what you type, changing teh into the, for example. And a host of Mac utilities will do the trick, too. Now Apple has built autosubstitution of text into OS X. Programs have to be modified to specifically support it; but once they are, they’ll all share the same substitution list, which you can see in the Text tab of the Language & Text pane in System Preferences.
In Snow Leopard, Apple finally cleans up OS X’s Services menu. That menu has been around forever, but its implementation has been surprisingly awkward. To access it, you had to go to the Application -> Services menu.
The new version of Apple’s QuickTime multimedia architecture in Snow Leopard is called QuickTime X.
Snow Leopard’s Preview app, now at version 5, sports some exceedingly useful fixes and refinements.
Apple has been gradually bringing Mac OS X up to speed in terms of accessibility features for users with physical disabilities.