The majority of people who use Earnings Tracker download it and install it on their own computer. They will, therefore, almsot certainly be the only person who uses their version of the application. For these people, it doesn’t make much sense to have to register with the application.
The next version of Earnings Tracker to be released will be a single user version, which will simplify the application by removing any code that is used to identify individual users.
I expect this new version to be released early next year.