Tomboy was removed from Ubuntu 12.04′s pre-installed applications because it used the outdated Mono library. Gnote is an improved port of Tomboy written in c++. It is the same note taking application, including most of the add-ins (more are to come). Synchronization support is being worked on.
Install Gnote in Ubuntu:
Gnote is available in Ubuntu Software Center, just search for and install gnote package. It may be a little out dated, if you would like the latest Ubuntu package install Gnote from ppa:gnote/ppa.
Launch a terminal from the dash or press Ctrl+Alt+T. Copy and paste following commands into temrinal and hit enter one by one to add ppa and install gnote:
sudo add-apt-repository ppa:gnote/ppa
sudo apt-get update
sudo apt-get install gnote
That’s it, enjoy!