At the moment I am using an email address and hashed activation code to sign a user up i.e.: They register online and receive an email that requires them to click on the activation link before their account becomes active. I don't want to use any info of theirs in the query string as I now have email and hashed code as a means of verification. I was checking through some of my on emails that I received from sites I have registered on and I saw some have a code as well as a referrer id which was simply the name of the company.
Could someone please explain to me what this referrer id is and how it is useful. I did google it but I still can't seem to find a clear answer that makes sense.