the online operation system

Because of the web 2.0 bonanza there are some projecst who wishes to provide an online OS and i am not talking about netvibes, igoogle or any of there "friends" ,
i am talking about projects who really thinking and trying to building a "full featured" OS like web site some examples are:
1.g.ho.st whom i saw there presentation and it was nice...



2. youOS that i think was the first one.


and there are a bunch of others here
All of them (well not all of them but most of them) are good looking, fun, cool and useless.
why useless?
For what do you need a web OS? and why would you like the copy the interface from your desktop OS to the web?
Don't get me wrong i am a strong believer in web 2.0 and i think that in the future there will not be a desktop OS as we know it now.
But why copy the same interface for online use? is that that smart?
this mistake is done over and over in the history... a quick example do you remember how the first cars looked like...? just like a carriage but without the horses.

If you look at old movies (from the 20s) you will see that they shoot them like a show in theater.
My point is don't copy what you know from the old world (IE desktop OS) to the new world (IE web OS) because it just doesn't work... invent something new...
please feel free to comment.