During Apple's "Back to the Mac" press event (happening now!), Steve Jobs introduced the Mac App Store, a Mac OS X variant of the hugely successful iOS App Store seen on its iPhone, iPod Touch and iPad products. Like the portable counterpart, the Mac App Store offers an app clearinghouse ("the best place to discover apps," in Apple's words), one-click downloads, both free and paid apps (which will share the same 70/30 revenue split between developers and Apple as the iOS App Store), and automatic installation and app updates. Apps you purchase from the Mac App Store will be licensed for use on all your personal Macs – we imagine you'll be required to authenticate with your Apple ID on each system.
While the Mac App Store will be arriving with copies of OS X 10.7, dubbed "Lion," this summer, Jobs revealed that Apple would be releasing this feature early. "We don't want to wait for Lion," Jobs said. "We're going to put it out on Snow Leopard, and will open within 90 days."
For any game developers who want to get in on the desktop-oriented gold rush, Apple is accepting app submissions beginning in November. At least for now, there doesn't appear to be any reason to worry about the relatively "open" confines of Mac OS becoming any more iPad-like ... Let's at least wait and see how this Mac App Store does first.