If a hire is made, the employer will apportion the bounty to everybody who helped sourced the final candidate, so it pays to spread these links where appropriate.

I don't understand this part. So let's say I recommend someone to apply for a job. I get the bounty? Who else would it be shared with?

If someone else shares my link to someone and that someone gets recruited, how does the system know that someone else invited him?

Cool idea anyway