This blog post is not considering the USB metaphor in context of Dropbox.

You wouldn't install Dropbox on someone else's computer just to get a couple of files. You would go online log into your Dropbox and get them from there.

Good point.

It's just that Dropbox becomes a little like Mozy then. The whole charm of Dropbox for me is interacting natively with the file system instead of having to log into a website and click around..

sure, I understand what you mean. But surely no one would really install and sync a 50GB Dropbox on someone else's computer?

The web front end allows you to have the best of both worlds.