Gina
Gina is a simple program providing virtual sticky notes for your desktop.
It has way less features than similar utilities; on the other hand, it is also smaller, having no dependencies except for plain GTK+.
It was started as a compatible clone of Nina, now known as Rhinote, and has not moved much forward since. To date, it still misses one feature which has been available in Rhinote since the early days, namely print support.
Gina is written in Vala.
Features
You can create and edit virtually as many notes as you want, each one in a separate window, all running within a single process.
Notes can be stored on file and loaded anytime. Since notes are saved as plain text files, it is possible to edit them using any text editor.
Keyboard shortcuts are provided for every action.
Resources
You can either pick any of the released versions of Gina from the releases section, or get a copy of the current development from the Git repository.