Share your unique referral link with friends via e-mail, Twitter, Facebook, carrier pigeon, or whatever you prefer. You can refer up to a total of 30 friends.
For a friend to sign up with your referral link, they'll just need to be a brand-new member with a Humble account. The rest is easy.
You will automatically receive up to US$12 in Humble Wallet credit for every new member you refer. You can spend Humble Wallet credit on awesome stuff in the Humble Store.