Since you're calling it a startup as opposed to just a project, I have to ask about business model. How will you make money off this?

I think you'll have a very, very difficult time monetizing this, as there are already dozens and dozens of free TODO apps. Unless you can carve out a die-hard niche that is 100% against signup and login forms, it will be difficult to compete with the others that are both free and easy to use.