how is the referral link working?

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as we know,everyone in mylot has got his/her own referral link,when you put it on a appropriate place,and when someone click it,it will go to the page of mylot index,and the link address will be changed,it that means when the one sign up into mylot,he or she is your referral? then how does it judge from?browser cookie or the previous link(your referral link)?if someone clear the cookie,does it keep the effect?i just curious