From Apple's Press Release

"With more than 1,000 apps, the Mac App Store is off to a great start," said Steve Jobs, Apple's CEO. "We think users are going to love this innovative new way to discover and buy their favorite apps."

The Mac App Store offers apps in Education, Games, Graphics & Design, Lifestyle, Productivity, Utilities and other categories. Users can browse new and noteworthy apps, find out what's hot, see staff favorites, search categories and look up top charts for paid and free apps, as well as user ratings and reviews.

Commentary
The release of the Mac App Store demonstrates that Apple's focus is not solely towards iOS and its associated hardware including iPhone, iPad, iPod, and Apple TV.

As more people and organizations are making the switch to Mac, Apple has leveraged the success of the iTunes App Store to roll out a new platform to bring Mac OS X users together with developers.  This will surely drive more users to the Mac and make it that much easier for switchers who have used iTunes and the iTunes App Store for their iOS devices to mirror the purchase experience on a Mac.  It is also a signal to developers that Apple wishes to bring more developers to Mac OS X.

We'll provide coverage of Mac App Store developments as the platform grows.