You should see a new icon in the taskbar for a launcher that includes the apps you've installed from the Chrome Web Store and a search box that works just like Chrome's Omnibox. The app launcher is great because it's there even if Chrome's windows have been closed and it's a faster way to open an app, perform a search or go to any other site. You can also use it for simple calculations and unit conversions. It reminds me of the Google Quick Search Box and a similar feature from Google Desktop.
{ via Chrome Story }