Report Offensive Message

Then again, not even all OS X apps go through the app store yet. If you're working an in-house app system, it never would, either.

The app store concept is designed to let the user find apps more easily. Just as not all OS X (or Windows) users know all the apps available for Apple products, not all Windows users (Or Apple) know all the apps available for Windows. The app store simply offers a one-stop shop and buy location for commercially-available apps. I doubt that either will be totally exclusive considering all the tech market download sites all over the place that most consumers don't even know exist.