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…
Sigh You're absolutely right. I guess, if there is such a niche, which remains to be seen, I maybe could limit the number of lists they can have before upgrading to premium?! If anyone has ideas, I'm more than willing to listen.
Just enjoy the ride and you'd be surprised what people will pay for. I don't care how many free todo apps are out there people will still pay for them. For examples, Things for Mac. Incredibly simple concept but its valuable enough that even I bought it a while back.