Apple announces Mac App Store
The App Store will get a dedicated desktop application that allows you to browse and buy apps, and even redownload previously-purchased ones. It also functions as a software updater for your purchased apps, much like the App Store on your iPhone. Apple's Software Update on the Mac is useful, but it only works with Apple's own software, so this is a welcome feature. (If you want to update all your Mac apps, not just the ones you buy in the new store, try a third-party solution like AppFresh.)
Steve Jobs has semi-denied that there would be a Mac App Store in the past, but now it seems that he was just denying that Apple would have to approve all software running on any Mac. Apple still controls what goes into the store, but that doesn't stop you from buying or downloading anything you want from the biggest app store of all: the Internet.