I like it a lot, nice job. Definitely reminds me of TiddlyWiki.

My main criticism is that there should be an explicit "save" button or link for notes. Perhaps it could be similar to the gmail "save draft" button, in that autosaves would disable or "gray out" the save button (nothing more to save). I think not having a specific Save button will confuse "average" users who have been trained to "Save Often!"

Other than that, I think it would also be good to be able to hide or "minimize" the vertical menu on the left (+,link,<paperclip>...) because I actually find it quite distracting. I feel like it breaks the flow from menu item to note- maybe moving it to the right might be good as another option.

Overall, quick to set up and easy to use- so those are winners! Nice work :)