Ubuntu offers a free 5GB cloud storage space for Ubuntu users known as UbuntuOne or U1. But since Ubuntu 10.04, Ubuntu has removed the default synchronization Indicator for some unknown reasons.
To get it back open up your Terminal window and type the following commands.
Add the new dedicated repository:
sudo add-apt-repository ppa:rye/ubuntuone-extras
Refresh or update the packages list:
sudo apt-get update
Install the UbuntuOne Indicator package:
sudo apt-get install ubuntuone-indicator
Start it as a program and Enjoy!