You can enable the Refer A Friend entry option to increase the viral reach of your campaigns by allowing users to gain additional chances to win when their friends enter the promotion.
This entry method allows you set specify a landing page URL and default text that users can share. You can also set the maximum number of friends that can be referred and how many entries are awarded for each friend that enters the campaign.
Within the entry form, after completing the required entry information, the entrant can share their unique link via Facebook, Twitter or email. Each new user that enters the campaign through that unique link will increase the chances of the referring entrant's chances of winning.