1.) no idea what %. I supsect 100% of the ones where people use the link corrctly work. We will check for those that file a support case where they believe they didnt get them because their friends entered the wrong info. Judging by the number of people that write in, vs the # of free snipes we give out daily it's in the low single digit %'s.
2.) We dont display who signed up through you for privacy reasons. Many people have their links out on their web pages, or eBay end of auction emails to their buyers, and all over. So it's not just their friends signing up but random people. We do maintain a table in our database with a list of all referals so we can always check if we need. It's all automated. If a person enters your userId or email address you get automatically credited.