The actual notification model makes Ubuntu One Windows rather annoying.
For each file synced/deleted/in deletion/syncing there's a notification regarding that. This makes the initial sync process a bit clumsy and messy.
It gets worse when you set U1 to sync every one or two minutes. Notifications from the initial sync and from the automatic sync are combined, and that's what I call confusing and disturbing. This creates lots of notifications and a very unpleasant experience. It's important to say that all this notifications confusion still happens even after the initial sync process, with all the deletions and additions.
In my opinion, when you click for the first time "Synchronize Now" only a notification, saying "Syncing...", or "Downloading your files", "Doing the initial sync process..." (I think that the metadata syncing information isn't relevant to the end user and should be merged into the "Syncing" string, please tell me if this deserves another bug) should appear for a while, giving the user some instantaneous feedback. Then, the user could forget about U1 for a bit while it's syncing, and get other things done. The spinning icon would indicate that U1 is still syncing, and the user could check the state of the sync trough it. When done, a notification should appear saying something like "Initial sync complete" or "Synchronization complete" or "Sync complete".
When a user inserts/deletes a file in the U1 folder, locally, I think that the icon should only start spinning. It's clear that the file is in the folder, and spinning would get the user to know that the file is being synced/deleted. However, when a file is inserted from a remote source (either a mobile device, another linked computer or the webUI), a notification should appear saying "Syncing x files..." (maybe it could change to simply "Syncing.." ,and the name of the file if it's just 1 file?), as well as the spinning icon. When done, something like "Synchronization complete", "Sync complete" should appear.
This though, would raise another question: if only one file is being synced, and it's a small file, then there would be two subsequent notifications, and that would be indeed annoying. I don't think that there's another way here, unless just showing the "Syncing..." notification. That would lead to a somewhat unpredictable behavior of the application and confuse the users.
About deletes/edits of files, I think that doesn't deserve a notification. Only a spinning icon.
This all scenery only in the event of the use of notifications. A Dropbox approach could also be taken: only show a notification when a remote file is added, for all the remaining operations just a spinning icon. I quite like this approach, but I must add I'm not the typical Ubuntu/Windows target user.
These are just by thoughts and ideas, and I'm by no means a software engineer or an interaction designer. Just a user wanting to help and share some thoughts. What do you think?
I would say that updating the tooltip would be a good way to indicate what is happening. So you can mouse over the icon if you want to know what the immediate action is, but it shouldn't pop up an bubble on each action.
I haven't used Dropbox to compare. However, I expect bubbles to only occur when I actually need to do something. They are a way of getting *my* attention that there is an action I need to perform. Something like "conflict occurred" would be a reasonable popup. Having it tell me it is doing what I asked it to do is a bit odd.