How come these days everybody wants your data in their cloud ?

To remove it you need to first remove the client, by following the instructions here: https://answers.launchpad.net/ubuntuone-client/+faq/778

1. Quit the Ubuntu One client
2. $ sudo rm -rf ~/.local/share/ubuntuone
3. $ rm -rf ~/.cache/ubuntuone
4. $ rm -rf ~/.config/ubuntuone
5. $ mv ~/Ubuntu\ One/ ~/Ubuntu\ One_old/
6. Open Applications->Accessories->Passwords and Encryption Keys, go to the Passwords tab, delete the Ubuntu One token
7. $ sudo apt-get purge ubuntuone-client* python-ubuntuone-storage*

However, there’s one step not listed there and you will notice since the UbuntuOne icon will still remain visible in your launch bar.

That’s the installer which also needs to be removed:

There will still be some leftovers which you can find using sudo updatedb; locate ubuntuone but to me they seem ok not to spend time to remove them (images, documentation and a python package related to ubuntuone-uploader).

Just to make another thorough check:

Enjoy your Ubuntu!

Later edit:

Ubuntu 12.04 is still extremly slow on my netbook (EeePC 1005px). While checking the output of the top command, I noticed another ‘one’ related service that was using a lot of my CPU (not constantly).

oneconf-service

A quick:

got rid of if, but apparently, it is linked to software-center too, and thus, it also removes Software Center. I’ve tried reinstalling Software Center, but it wants to bring back oneconf. So NOPE.

Since I disliked Software Center – it was offering the payed things first – I agreed with uninstall.