I'm really excited about this. Thanks for including klein's old submission as well, that's a really enjoyable read. Ubuntu's Unity 8 is another take on this, with its scopes.

I'd prefer it if the only apps I had on my phone were rss/podcast, email, browser, ereader, camera, maps, music, and dialer/sms/whatever. I would really prefer that everything else I use be in the browser. I need a bit more on my laptop/desktop for writing, and various CLI applications (and hopefully my phone and my computer will be the same machine before too long). With that in mind, it feels to me like these really basic applications should be baked into the operating system more than they are now, so they look like the sort of interfaces described in the intercom.io post. The key is that the content from the applications bubbles up into the common interface.

Now that I'm thinking about it, in a way, this is why I enjoy using the command line more than graphical interfaces for a lot of purposes.

EDIT: this also reminded me of something I was thinking of a few months ago. I wish email would be treated more like a cross-platform notification system. I know it already is that, but I think it should look more like native applications currently do on mobile OSs, with actionable buttons that take me directly to the relevant webpage, app, etc., without having to go into the email app to see a full message. If it looked exactly like what Android notifications currently look like, I think that'd be perfect. It should be less about communication, more about notification. I was hoping Mozilla would push something like this with Firefox OS, but it doesn't look like they are.