Drush is a very nice framework for building CLI tools. But it's not a proper ecosystem until it has a todo app.
@Todo is intended to provide developers and administrators with a lightweight task-recording tool that can replace burying @todos in your code. Those can sometimes be useful to inform others of future intent, but are a pain to actually track your own actions.
With new or tiny projects, I often find myself putting high-level notes in an issue tracker somewhere but jotting down more detailed action items in a hard to manage scratch space... @Todo provides cleaner structure and is easily there for me on the command-line when I want to drop a quick thought into the queue.
Again, it is not intended to compete with a real issue tracker. Feature requests oriented at making @Todo scale to more users or more issues will likely be rejected.