Google has yet to officially launch the Chrome app launcher, but there's a simple way to get the launcher right now if you use Windows: go to this page and click "Get the launcher" (the link only works in Chrome for Windows). If you're not signed in to Chrome, you'll need to do that. Probably Google uses Chrome's sync feature to enable the launcher.

Chrome adds a new icon to the taskbar and a new desktop shortcut, at least in Windows. The launcher shows all the apps that are also displayed in Chrome's new tab page. It also shows a search box that lets you quickly launch an app. Engadget reports that the app launcher has been automatically added for some users. "On our own PCs, the installation placed the launcher app on the start page, taskbar and desktop for Windows 8 and in Windows 7's menu bar." Chrome's launcher is connected to the new-style Chrome apps. Google wants to move from the old apps that were mostly bookmarks to some new apps that work offline, use powerful APIs that integrate with web services and devices like USB drives and Bluetooth speakers.

Some examples of new-style Chrome apps: Google Keep and Google+ Photos. Both apps work offline, while Google+ Photos automatically uploads the photos from an SD card. More examples here.

It's interesting that Chrome's Web Store is now all about apps. Extensions and themes are still available, but you need to explicitly click "extensions" or "themes" to find them. They're no longer promoted on the homepage and search results show the apps first.
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