"Keepnote is great in organizing hierarchical notes. It simply creates an easy to use tree where notes can be grouped, childs created etc.. The only sad thing is that in the default repository is the last "stable" release, which in my experience is some slow and contains bugs. Instead i can suggest to use the last created beta version 0.7.9, to find as a PPA or different packages on the website. However unfortunately it seems the development has stopped in 2012 and no enhancement of such a great app will be available. But anyway as said the last released beta is the best choice."