When using Todo List Tools you are connecting to a Remember the Milk account. Thereby you are exposing data within that account.
In order for this application to authenticate itself to the Remember the Milk API, it directs the user to the Remember The Milk website to login and give it the necessary permissions. This application does not collect these credentials; they are only used by Remember The Milk to generate an authentication token for this application to use.
Once authenticated to Remember the Milk, this app retrieves information about
every list and smartlist found in the account, the lists themselves the user
selects and the tasks within those lists.
This application uses the collected data mentioned earlier in this document to present aggregations and calculations on that data to the user.
The only piece of data stored is the authentication token. That token is stored in a configuration file on the user's device. When the user closes the application, all other data such as lists and tasks are gone, since it only resides in memory.