There are a few reasons why this could have happened:
1. Your friend did not use your Unique Affiliate Link during registration.
The referral cookies which are sent through the referral links you send your friends are what tells our system that you are the person who referred them. If your friend did not use the unique affiliate link you sent them to sign up as your referral, our forum will record the sign up as a walk-in, independent of any personalities and referral IDs.
2. Your friend may not have reached the minimum 5-post requirement to credit you with the referral.
Our forums require each referred person to have a minimum of 5 posts before we award you with the referral. This is to uphold the quality of the forum, and to discourage users from abusing the referral system simply to earn points.
3. Your friend may have signed up for our forums using the same IP address that you are using.
To prevent and discourage abuse of our referral system, we have disabled the awarding of points for people who refer "friends" using the same IP address as the referrer.
4. Your friend used your Unique Affiliate Link but changed the computer he/she used to sign up.
Since cookies stored in your friends' computers are needed to track the referral back to you, if he/she changes the computer she uses during registration from the one he/she originally used to click on your unique affiliate link, you will not be credited as the referrer when he/she signs up.
5. Your friend used your Unique Affiliate Link but deleted his/her cookies on the computer.
This is pretty much the same as the item above - if your friend uses a computer which doesn't have the cookie from your Unique Affiliate Code, you will not be credited as the referrer when he/she signs up.