Google is changing Chrome's policy to no longer allow installation of extensions in any way other than through the Chrome Web Store. However, their wording is a little unclear. They state:
We’ll continue to support local extension installs during development as well as installs via Enterprise policy, and Chrome Apps will also continue to be supported normally.
But it's unclear whether they mean ChromeOS apps, or packaged apps as defined by an "app" section in the manifest.json. Do they mean packaged apps can still be installed outside the Chrome store?
http://blog.chromium.org/2013/11/protecting-windows-users-from-malicious.html