Question:

How can we give activity points for referrer and tracking information of referrer and new registered member?

Answer:

When a user wants to send invitation, a link will be sent to the user which consists of the referrer id. Once new user clicks on the link it redirects to the registration form and id will be stored in cookie. So, once the registration finishes  referrer will be rewarded with activity points and referrer will be added as friend to the new user. and it notifies about the registration of new user to the referrer.