We believe it should be easier for users to discover web apps and for developers to reach a large audience. That’s why today at Google I/O, we announced the Chrome Web Store, an open marketplace for web apps.
Tell me, how is this different from Google Directory? Or Yahoo Directory? That you have given it a fancy name? (It still is for websites, bah!)
It doesn't seem very different from a simple directory, but...
(1) It "installs" a shortcut to the apps, so that they "feel" more like an app than a website,
(2) Google will add value to the "directory" (through ratings, statistics, and a search process optimised for applications)
(3) It's integrated with payments, so that developers can sell premium applications.