This was posted in the Ubuntu Forums but received no response, so I'm re-posting it here (with minor updates) in hopes that it will at least get some comments.
Recently, I moved a large amount of contents (a few GBs) within the Ubuntu One folder (through cut-and-paste). Then I discovered how Ubuntu One does this is to remove them on the server side and upload all the files again in the new location. Obviously, this is undesirable because of the hefty uploading involved. Worse, since I have two computers synced to the same account, it is double the amount of traffic. Each computer took about one day to finish synchronising.
Firstly, can anyone confirm that this is actually what's happening when we move folders? I'm using Ubuntu 10.04, by the way. Secondly, is there a way to cut-and-paste stuff within the Ubuntu One folder without uploading again?