If you upgrade, you can collect players data information. This include contact information and what the players answered on your quiz. This has tremendous value: not only you can contact the players of your quiz and turn them into customers but if you have designed a profiling quiz, you will know a lot of information about the player and make your approach more personable. You can also export a report for each player, containing their contact information and what they answered.
The premium plans are based on features
$19/mo for unlimited players' profiles, data export
$39/mo for a non branded version of your quiz and access to statistics