Here are the steps to look up your referral history:
1. From the homepage, click on the profile button located under your user name at the top right of the page.
2. Enter the security question and your password.
3. Scroll down to the middle of your profile page and you will see a box with your referral history. Your referrals will show along with their status. "Pending" means they have not joined yet (remember, they need to confirm their email address to be considered a "joined" referral.)