As a matter of fact, I do not like the idea of rewards in the form of money including the existing one HD has. It sends a wrong message to the ones who do not use HD regularly.
For me, I didn't sign up with HD before because of the "get paid to participate" offer. I understand that it's a way of putting value to members that actually contribute valuable information/interaction but it kind of differs from the concept of sharing. You can replace that with a temporary badge and a count of how many temp badge a member received in the lifetime of their account.