You only get referral credit for them if they use the referral link from your profile. If you just mention the site to someone, they come here, and sign up; then it does not connect it to your profile. So you very well could have more than that, but they are not credited because they did not use your referral link.
I put my referral link up on almost every site I sign up for...so I have no clue who these people are. >.< I know at least one of them, but only cause they are active on E.