Affiliate networks administer programs for individual merchants, handling all the work involved, while generally providing tracking and reporting capabilities to their affiliates to help them keep tabs on their revenues and determine which products or services are producing the best returns. These tools can be helpful to an affiliate in fine-tuning the line of products she decides to promote on her site and, ideally, increasing revenues as a result.
As an affiliate for Boatbookings, you will receive 20% of their revenue - effectively meaning your commission will be about 4% of any sales from your referrals. You also receive 10% of any commissions Boatbookings make on repeat customers who were your referrals. They do have a minimum charter value of 3,000 ($/€/£/etc) before commissions are earned.