Nah, this one's a good ol' fashion paper notepad. It's much more satisfying to burn the pages. And so I know I can write whatever I need to write and no one else will ever see it.
A fairly safe and reasonable excuse to start a fire.
Seriously though, that does kind of sound like a neat idea. Helping you vent your frustrations in a completely private way, while I suppose symbolically 'purging' them too. They won't bother anyone else.