you want to do a bonus for only those that were featured in previous contests. You want it to be a first time bonus only.
Yes, exactly!
I want to give extra incentive to create this wave from a newbie that was featured to the next contestant paying it forward.
Imagine if only a small number of them took the hint or the challenge - s/he could end up with a big bonus.
It is to help newbies to overcome the inertia!
I liken this to being at a dance party and the newbies don't know anyone. Then, someone invites him or her to dance. Then, someone announced that if s/he then invite another newbie that have not been invited to dance yet, s/he can get a special prize in addition to all other prizes.
The only way I can see doing this would be to manually check to see what entries are from those that were previously entered and then double check to see if they had previously entered the contest...
How about this:
Set the rule that their entry must include the entry url - link to the entry that they were featured. The link must be at the top stating the fact.
The entry must declare and state the rule about the bonus to indicate that rules for bonus was follower.
Anyways, I am open to suggestions, but, I think all entries should identify themselves if it is for the bonus also - it is their responsibility.
The judges could encourage the current and past participants to help their featured newbies to enter to win the bonus and help them declare their meeting the requirements for the extra bonus. Perhaps, the judges can give it a name?