1. Your company's name 2. How much the employee referral bonus is (or a range depending on the type of candidate) 3. Whether or not you pay an external referral bonus and how much that is as well 4. Any details on how successful the bonus program has been?
Companies would push the issue, telling you this a chance for your friends to work with you.
I tended to consider the offers an insult, when you considered 1) the were saving 20 to 30K per candidate, as that was what the head hunters charged. 2) headhunters do not actually know the person so they are not really vetted the way a friend would be vetted. Because who would recommend a friend who would not be a good worker? A headhunter will all day and night.
But I suppose if they offered a good incentive, people would actually recruit ANYONE not just qualified people.