Wow I had no idea! StackVM is all html and javascript and we've taken great care to make sure it works on all browsers without any silly plugins.
I agree that they should avoid plugins if their app works fine on html & js, however, this is unlikely with the current html and js. (Think of playing games). Maybe with the improvements in HTML5 this might be achievable, but currently it's not.
1. This isn't a web-based remote desktop client. 2. Your concept of "something real" is clearly different from mine. 3. Their app appears to work very well, in my opinion, without having to resort to browser plugin messiness. 4. This particular solution's primary value proposition is that it will work on almost any recent browser, without other installed software.