We've just made it easier to register for a free account of our SimpleDB backup solution by relaxing the requirement to gather your AWS credentials at the sign up stage. Now you can register for an account but only enter your details when you want to, plus you can purge your credentials from our systems whenever you like - if you prefer after every backup has been completed.
As a side issue, we have fixed a small display bug where an error pertaining to missing credentials was being displayed in the browser as a raw error message rather than being trapped in our code and presented more appropriately.