Google will block local extensions in Chrome 33 for Windows, disable existing ones not in the Chrome Web Store. I assume this has to do with the current spam issue of legitimate extensions being bought and then “updated” with spyware, ad injection, and so on.

Google today announced it will block local Chrome extensions on Windows as of version 33. As a result, Windows users will only be able to use extensions for the company’s browser that they install from the Chrome Web Store.