In general, Metro applications must go through Microsoft's app store.

There are three exceptions:

  1. You can add self-signed certificates and side-load.  This is actually quite
     easy for developers, but a no-go for most people;
  2. You can push corporate apps out to Windows 8 Enterprise devices; and finally,
     the way Chrome is doing this, which is
  3. Browsers are treated really, really specially.

Microsoft is still bound by the US anti-trust agreement to allow other browsers on Intel computers. In order to facilitate that with the Metro environment, on Intel-based Windows 8 computers only (i.e., not Windows RT tablets), the DEFAULT browser may optionally provide a Metro interface, even if that browser does not come through the Microsoft store.

It is this exception that Chrome (and, in beta, Firefox) is exploiting.

This trick only works for browsers. And, further, the way it's implemented is an insanely stupid horrible pain in the ass. I really like IE10 for tablet browsing: it's very fast, it has outstanding touch support, and it's actually a great rendering engine. On the other hand, you can pry Chrome out of my cold, dead, festering corpse's fingers when I'm on Windows 8's desktop. So the logical thing would be to use IE in Metro, and Chrome on the desktop.

But you know what? You can't sanely do that. Only the default browser gets to live in Metro. And when I say default, I really mean default. If you set Chrome as your default browser, then you cannot launch Metro IE--the ONLY Metro browser you can launch is Chrome.

It's the little things like this that are making it REALLY hard for me to stay a Windows 8 supporter. The more I use it, the more the little, idiotic things like this are making me go crazy.