I just discovered that Circus Ponies Software ceased to exist. Their Notebook programs are no longer available. Their site is reduced to a short note. Their users forum vanished.
This is bad news for all of us who rely on their eminent Notebook for outlining, note taking or note keeping. I myself have more than 10 years of notes in my notebooks. Notebook 4 currently works fine, but I fear that it will no longer do so after the next OS X upgrade. I will start looking for an alternative. If you use NoteBook, you may want to do so too.
You can find more information about Notebook and the way I use it on my tech tools page.