Ubuntu One is not a “proprietary” service
Ever since Canonical started with Ubuntu One (or “U1″), people have been crying and whining about it being a proprietary pile of goo. For someone who has been active in the free software world for a long time, and still has his brains about him, this makes no sense whatsoever.
Yes, it is true that Canonical has not given up the source code for the U1 server-side software. And if you stop right there and proceed no further down the train of thought, you will probably come to the conclusion that it is proprietary software—and you would be wrong. Why?
Because the U1 client is free software, that’s why! It seems to me that we have forgotten what client/server applications are. Remember that HTTP is a client/server application, as is SSH, as are so many other types of things. It doesn’t matter if both sides have source code available, when it comes to client-server stuff.