By donating, whatever the ammount, you help us maintain and develop our game. Besides, if you donate at least 10 € you will be promote to a full member for one year,
which means that you will have the possibility to create your own games with your own parameters.
Top is also that the icon 
behind your login will be replaced by a better one, I say 
Don't forget then to indicate your logging in the game in the box 'purpose' when proceeding to your donation.