Every Tesla owner is in the referral program. If you get something like 20 referrals at various times you could get a car. These guys own a Tesla, I think two of them between them, and so could eventually earn a car. Even I am a craven person who get something if you use my referral code to buy a tesla. You get $100 a year for at least 4 years in supercharger credits (that's like $400 a year in a regular gas car cause EVs get the equivalent of around 100 miles a gallon in gas :-)).
I get virtually nothing unless I get 20 of them - not sure of the current program but so far my life time total referrals is: 0. If you have questions and want to ask someone who has owned two different ones since 2012 ask me questions. If you want to buy a tesla, I have a referral link too, contact me via email on my account here, maybe hackernews wouldn't like me to just put it out here.