Please read “How can I tell whether Ubuntu One file sync is working, and what progress it is making?”.
Folders are the first thing created, and it's entirely possible the syncdaemon is chugging along doing its thing. You haven't mentioned what version of Ubuntu you're on, so I don't know what performance to expect from your client (it's improved drastically with each release).
How many files and folders are you trying to upload, and what's the total size? If you have a lot (tens of thousands) of small files, you might be experiencing the worst performance problem we have right now (we are fixing it for 11.04). If you have very large files that don't finish uploading between network glitches or hiccups (such as suspending your machine), it might be stuck reuploading the same file over and over; this is another issue we're fixing for 11.04.
If it turns out that progress isn't happening (and the above article doesn't get you to nudge it in the right direction), try first quitting, restarting and connecting the syncdaemon. The way to do that will work across all versions of Ubuntu right now is by entering the following in a terminal:
while ! u1sdtool -c >&/dev/null; do sleep 30; done
this should be enough to “unstick” the syncdaemon from whatever got it into trouble, and set it on its way. Use what you learned in the other article to track progress, and restart it if it seems stuck for too long.