The fonts are a bit rough, i think cannot read them well and I got 28 and 0 eye problems so people with more age and eye problems will have a hard time reading it. maybe making it a little bigger and getting some better fonts try www.typekit.com or something.
Anyway great design, the app in itself is not useful for me as ConceitedCode6 pointed I like portable todo lists, maybe an Iphone app ?
Congrats !
I'd change the default font to something more readable, remove the coffee stain from the page, let people flip a few pages ahead (otherwise, why use the notebook paradigm?), and change the "i'm a new user" flow -- the form field animation is pretty and ingenious, but it's also confusing, so I don't think it's worth it.
Apparently, the concept is that you only have two queues/stacks, "now" and "later." I do agree that this isn't very intuitive from the design.
This is on my to-do list, adding another font ;)
It actually started life as an iPhone app, you can download it for free for Android/iPhone