One of the things that pissed me off about Copy, and in fact made me not want to use them literally 10seconds after I signed up, was they cached referral codes. I first learned about Copy by following someone's referral link, but I didn't sign up at the time. A few days later I decided to sign up so I head over to copy.com and do so. Low and behold, I've someone managed to sign up as a referral despite not following a direct referral link to get there. My account (including personal info) was visible to a random reddit users who I didn't actually know.
Only your first name and last initial are shown to the person who referred you. Two people even omitted full names entirely, so I only see two letters and how many days ago they signed up.