Todo.txt Touch requires that you have a Dropbox account in order to be able to capture the todo.txt file elsewhere than just on your Android device. Eventually, we hope to support other cloud sources.
There are already a multitude of decent task managers for Android, but Todo.txt Touch is a minimalist, plain-text focused solution we built to learn by collaborating on Android development.
Interested in joining in? Fork the project and talk to us on the Todo.txt mailing list.