Interactive

You should always be very clear in your legal rules that participation requires the players to be 13 years and older. In your registration pages you should ask for date of birth, instead of stating “YOU MUST BE 13+ IN ORDER TO PARTICIPATE” as this type of language may actually encourage users to submit a fictitious age. Your online system should not allow them to play or database their information if they enter a date of birth under 13 years of age, and it is also a sound practice to bar such users from attempting further registrations on your system.

Yes, quite often if you reward a person for sending on your message with an additional entry or another game play you will have much better results in increasing the number of people who will do that for you.

You could utilize a form of CAPTCHA ("Completely Automated Public Turing Test to tell Computers and Humans Apart"). These systems force a human-eye to read a randomly created selection of letters and characters and make the person re-type the characters they read. This system keeps users honest by preventing automated floods of entries via scripted or robotic code. In a well-designed CAPTCHA, characters are very difficult for automated systems to discern and read. In addition, tracking of IP address access speeds/frequency should be tracked in order to assist in throttling the rate at which any single user should be able to participate. Quality data centers will also provide a level of monitoring and defense against certain types of DDOS (distributed denial of service) attacks.